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Upstream (NegPy) review log

SwiftInvert ports NegPy's negative-inversion pipeline; NegPy (~/Documents/code/NegPy) keeps evolving. This file records the last NegPy commit we reviewed, so "what changed since we last looked?" always has a baseline. Keep it current: every upstream review ends by updating the marker and appending a history entry.

Last reviewed

commit:   a09cc46  ("change: Linear RAW defaults to off (#717)")
reviewed: 2026-07-31
fixtures: Tests/Fixtures/ dumped from 0369b10 except lab_color (partially
          re-dumped from a09cc46, 2026-07-31, with the pure gamut boost —
          the b8c596c dump had carried the interim in-boost skin damping).

How to run a review

Preferred: run the /negpy-review skill (.claude/skills/negpy-review/) — it automates the steps below, applies the port/skip judging rules, and updates this file. The manual procedure, for reference:

  1. cd ~/Documents/code/NegPy && git fetch origin
  2. git log --oneline <last-reviewed>..origin/main — the unreviewed range.
  3. Focus the diff on the pipeline we track: git diff <last-reviewed> origin/main -- negpy/features/exposure/ negpy/features/process/ negpy/kernel/image/ (normalization.py, logic.py, models.py/EXPOSURE_CONSTANTS, the WGSL shaders). Also check whether the characterization goldens moved (tests/test_scene_linear_relocation.py, tests/test_characteristic_curve.py) — golden changes mean a deliberate default-look change upstream.
  4. Decide per change: port / deliberately skip (record why) / not applicable (UI, camera capture, CPU-parallelism, stages we don't ship).
  5. If constants or kernel semantics were ported: pull NegPy, re-dump fixtures (uv run python ~/Documents/code/SwiftInvert/scripts/dump_fixtures.py from the NegPy repo — check the dump script against upstream signature changes first), update K / kernels, make test.
  6. Update the Last reviewed marker and append to the history below.

Review history

2026-07-31 — through a09cc46 (0.45.0-dev, 10 commits)

Headline: upstream REDESIGNED the skin protection we ported yesterday. bfcd90a + fb94aed replace 1b900ab's in-boost damping (what our 2026-07-30 port ships) with a separate operator, after measuring the interim design's flaws: the hue-only 52±25° mask couldn't tell a face from a red car (~40° sits in-band), it was inert at Chroma 1.0 (a face arriving sunburnt from the print curve got nothing), and the first replacement's wide chroma window reined sunsets at weight 0.98. End state at tip:

  • The gamut-aware knee stays exactly as we ported it — but with the skin term REMOVED from inside it (pure gamut math now).
  • Skin Protection is a user-facing Lab control (skin_protection, default 0.5): skin_chroma_rein, a one-directional soft chroma ceiling (ceiling = 22/strength, softplus knee from 0.6×ceiling, scale blended by mask weight; a*/b* together so hue and L* never move) applied AFTER the saturation scale and independent of it — it also catches skin that arrived over-chromatic from the curve, and reduce-only means saturation 0 still reaches true grey and it can never overshoot the gamut the knee fitted.
  • The mask is the axis-aligned CIELAB skin locus: hue Gaussian 52° σ20 (was ±25), one-sided chroma window full ≤35 zero ≥60 via smoothstep (skin C≈12–40; pure red ≈104 drops out entirely), lightness rolloff below L15/above 95, chroma-gate 2 for hue stability. Measured weights after the tightening: skin 0.95–1.00 vs sunset 0.04, terracotta 0.18, brick 0.25, autumn leaf/rust 0.00.
  • Their goldens provably unmoved (no skin-band pixels in the relocation frame); their WGSL parity test was strengthened after discovering a dead GPU mirror could pass the old one.

PORTED 2026-07-31 (same day, user approved). Landed exactly as proposed below: the boost is pure gamut math again, skinProtection (default 0.5, keyless sidecars adopt it like upstream) + skinChromaRein both sides, fixture parity pinned at 0 in both harnesses, lab_color re-dumped from a09cc46 (yesterday's b8c596c dump still carried the interim in-boost damping — the two boost cases moved again and our pure implementation matches at 1e-4), and the dead-mirror lesson became a parity test whose PRECONDITION asserts the rein moves a deliberately warmed frame (mean > 2e-3) before checking GPU==CPU. Known cost, accepted: default-on rein dispatches colorPop every frame — bench 4.6 → ~7.2 ms preview (still ~140 fps). 185 tests green.

Original proposal, for the record: remove the skin term from gamutAwareBoost (keep the knee), add skinProtection (default 0.5) + skinChromaRein in colorPop after saturation, both sides; pin skinProtection = 0 in the GPU fixture parity settings (fixtures predate the control — same pattern as preSaturation); colorPop activation gains the new term (default-on means the pass always dispatches — bench it); dedicated coverage that actually exercises the rein (their dead-mirror lesson). No fixture re-dump (apply_saturation's new kwarg defaults to 0.0, so the dump script's existing calls are semantics-stable).

Not applicable: a09cc46 Linear RAW defaults OFF + b6d9b8e scanning setup wizard — their onboarding defaults for uncalibrated setups (the wizard turns it back on); our linear rawpy-style decode is the pinned reference contract, unchanged upstream. e62aacb filmstrip scrolling, 7528f9c favourites panel, df91cb4 Filtration reset icon, d1a3b61 IR dust fixes, 076e676 test-junk cleanup, 16b8f6d-style prefetch order (16b8fd6 — their prefetch; we retain sessions, no prefetch).

Still open (carried over): colour ring-around (±4cc/2cc spec), 91a1b78 tunable targets (user-initiated only), the mixer band re-tune.

2026-07-30 — through b8c596c (0.45.0 tail, 10 commits)

Kernel status: no golden moves, no constants drift — but three port candidates, one of which is a bug-class we share.

PORTED 2026-07-30 (same day, user approved) — items 1 and 2 (see the commits for full detail): Separation Damping landed with the exact gain formula, ref spread 0.35 as a new constants sync point, and the population-reversal contract tested both ways; gamut-aware Chroma landed in LabColor + colorPop with the skin band, bisection and knee — the dump script's lab_color case was repaired at the same time (frozen verbatim apply_vibrance for our SwiftInvert-maintained control, upstream apply_saturation for the rest) and lab_color partially re-dumped from b8c596c: ONLY the two boost cases changed, desat/in-gamut/vibrance byte-identical, and our Double implementation matches upstream's float32 fixtures at the 1e-4 gate. A dedicated tight CPU/GPU test (mean < 1e-3, max < 0.02) guards the path their transposed-matrix bug hid in.

Original proposals, for the record:

  1. Gamut-aware Chroma + skin-tone protection (1b900ab) — a flat Lab a*/b* scale preserves hue, but overshooting pixels get hard-clamped PER RGB CHANNEL afterward, which shifts the visible hue (their measurement: a 1.2× push clips 6.3% of a realistic population, mean hue error 8.65° on the clipped set). Fix: bisect each pixel's true in-gamut headroom (10 iterations) and soft-knee toward it; in-gamut pixels stay byte-identical; pulls (<1.0) unchanged; skin-tone hues get a gentler push. Our colorPop has the same hard clamp (clamp(lab_to_rgb(lab), 0, 1) after saturation/vibrance/mixer) — the bug class applies verbatim. Port = LabColor.swift + colorPop MSL both sides + skin-band constants; CAUTION: changes apply_saturation semantics for clipped pixels, so the lab_color fixture must be re-dumped (requires the dump-script adaptation first) or its clipped cases recalibrated. Medium effort. Their war story worth keeping: a transposed RGB↔XYZ matrix inside the bisection masqueraded as float precision noise — verify our port with their tight CPU/GPU gate (~1e-4), not just the 0.04 parity bar.
  2. Separation Damping (d86a5aa, separation_damping τ 0…1, default 0 = byte-exact off): makes the dye-separation k chroma-selective per pixel — h(c) = (c0−c)/(c0+c), k_eff = k^((1−τ)+τ·h(c)) on the RMS dye-density spread above base — so a push lands on muted colour and REVERSES on already-extreme colour (gain crosses 1.0; no flat k reproduces it: their Ektar sample reads ×1.37 on the least-coloured decile, ×0.89 on the most). The per-pixel-targeting idea we ported and retired, reborn as a modifier of the surviving control: maps directly onto our printSaturation (identity dye matrix → k_eff around the achromatic mean). Only meaningful when printSaturation ≠ 1 (grey out at 1.0, like upstream). Kernel both sides + one constant (their c0 reference spread); no re-dump. Medium.
  3. Proof-ladder rotation (a2455ab) — PORTED 2026-07-30 (same day): TestStrip gained orientation 0–3 (logical grid rotated under the fixed display grid; bijection + axis-purity tested per orientation), rotate buttons/⌘[/⌘] intercepted while a strip is up or building, labels/preview badge/picks orientation-aware, orientation sticky for the session. Documented divergence: upstream assembles all four orientations from cached tiles; we re-render from the warm tower (~one strip build) instead of retaining 25 preview-size tiles.

Noted: the ring-around spec at the tip is now ±4cc in 2cc steps (was ±2cc/1cc when first proposed) — still carried as an open candidate.

Not applicable: d982c4b zoom-button alignment (Qt), b8c596c tethered-capture deletion for bodies without a capture target (camera scanning), 4aa1001/540cd9a/65c7667/9714664/1869f2e changelog/screenshot/docs churn.

Still open (carried over): colour ring-around (above), 91a1b78 tunable Auto Density/Grade targets (user-initiated only), the on-scan Color Mixer band re-tune pass (ours).

2026-07-29 (second) — through 723e2c5 (0.45.0 release, 12 commits)

Headline: upstream DELETED the per-pixel Dye Separation — the control we ported this same morning — after measuring it redundant with Print Saturation. The three-commit saga (3ca2229 → 1d02071 → 3fb5ca8) ends with only the matrix-slot density saturation surviving, renamed dye_separation (default 1.0, slider 0.25–1.75, per-channel trims). The range's golden-file touch is comment-only (default annotations; no numeric move — both retired states were identity).

The saga, for the record (each step supersedes the last; only the end state matters for porting):

  • 3ca2229 measured the mask's problem: the 0.4 spread gate put the sigmoid half-point at 0.44 D spread — the p90 of real frames — so ~90% of pixels sat on the mask's flat top and the control acted as a near-uniform gain; per-pixel deltas correlated r=0.94/0.97 against Print Saturation on two real frames ("a second Print Saturation"). Fix: gate 0.4 → 0.12 (median-spread calibrated), correlation → 0.64/0.75.
  • 156252a widened the desktop slider; 1d02071 gave the positive branch a ×3 gain (muted pixels have tiny deviations by selection, so k−1 barely moved them) and returned the slider to ±0.5.
  • 3fb5ca8 concluded "the two density-domain colour controls read the same on real frames" and deleted the per-pixel block from BOTH engines (kernel block, WGSL constant, UBO slot, dye_separation_spread_scale gone); density_saturation(+trims) renamed dye_separation(+trims); their sidecar migration DROPS retired per-pixel values.

PORTED (RETIRED) 2026-07-29 (same day, user approved) — the per-pixel dyeSeparation is gone, converging on the end state. Our port (this morning, UPSTREAM entry below) was the ORIGINAL 0.4-gate variant — precisely the one upstream measured as r≈0.95 redundant with our printSaturation; porting the intermediate fixes just to land where upstream started from would have been churn. Removed: the kernel block from BOTH ReferenceCurve.swift and NegPipeline.metal, K.dyeSeparationSpreadScale + the DYE_SEPARATION_SCALE MSL literal (that constants-sync point is closed), the CurveUniforms field + pads (stride 272 → 256, LayoutTests re-pinned), the settings field + decoder line + history label + UI slider (tripwires 50 → 49). Mirroring upstream's migration, a sidecar dyeSeparation key from the field's hours-long lifetime decodes IGNORED — pinned by a new DensityChromaTests retired-key test (the suite's dye-separation behavioral cases dropped with the control; the sign-selects-population contract is upstream history now). The Lab vibrance help text now points at Print Saturation as the density-space counterpart. printSaturation STAYS under our name — a recorded cosmetic divergence (upstream calls the survivor Dye Separation; renaming would collide with the retired key in same-day sidecars). UI range kept 0–2 (upstream 0.25–1.75; derive clamp 0–3 unchanged). Per-channel trims remain not-ported (recorded skip). NO fixture re-dump (identity in every dump config). All 167 tests green (incl. GPU/CPU parity with printSaturation 1.4 active); bench 4.0 ms/frame steady state; app renders headlessly. CLAUDE.md updated — including its tripwire counts, which had gone stale at 48 during the morning port (now 49) — and the constants-sync list.

Carried port candidate updated: db37476 widens the colour ring-around (item 3, still to port) to 2cc steps out to ±4cc — 1cc rungs were unreadable on a preview-sized mosaic. RING_CC_STEP 0.05 → 0.1; any port should use the new spec.

Not applicable: 4f4d7a1 broken live view no longer kills the capture session (camera scanning), 4ee5267/7dc7903 Analysis-panel info button + guide-window centring (their Qt help UI), 111492b IR channels from 64-bit HDRi RAW DNGs (retouch/IR loading), 35b6994 crosstalk Separation → Strength slider rename (their crosstalk UI/docs — renamed to avoid colliding with the NEW Dye Separation; no math), 156252a desktop slider range (superseded by 3fb5ca8), 2f91a98 version bump/discord URL, 723e2c5 user-guide churn.

dump_fixtures.py: still broken ≥de79e13 (lab_color apply_vibrance import — carried); the 3fb5ca8 apply_characteristic_curve signature change is benign for the script (no saturation kwargs passed; new dye_separation default 1.0 is identity).

Still open (carried over): colour ring-around (b646e23 + db37476 spec); 91a1b78 tunable Auto Density/Grade targets (user-initiated only); the on-scan Color Mixer band re-tune pass (ours).

2026-07-29 — through de79e13 (0.45.0-dev, 9 commits)

The chroma stack was rebuilt upstream across three commits, with TWO golden moves — the biggest pipeline reshape since 127bcd7. End state:

  • 7bc8bdc Print Saturation (density_saturation, default 1.0, + per-channel trims): density-space saturation — an achromatic-projection matrix k·I + (1−k)·J composed into the paper dye-crosstalk matrix slot, applied to density-above-base AFTER the H&D curve, so its push scales with what the curve left in each channel (shoulder-compressed channels move less) and composes per paper.
  • c0d6ff0 (golden move) folded Dye Mute into that density-space slot as a grade-coupled damping of density_saturation (default OFF, was 0.25) and renamed Lab Saturation → Chroma.
  • de79e13 (golden move) replaced Dye Mute AND Lab Vibrance with one signed dye_separation (−0.5…+0.5, default 0): a per-pixel spread-masked rescale of dye-density separation inside the print-curve kernel — positive boosts muted pixels (vibrance), negative compresses already-separated ones (true anti-vibrance, which Lab never had); the sign flips the mask's TARGET population, not just the direction. Lab Vibrance is deleted (LabUniforms shrank; apply_vibrance gone).

Bookkeeping — two records close/change:

  • The Dye Mute skip is CLOSED, vindicated: the control we declined (2026-07-17, reaffirmed 2026-07-27) no longer exists upstream; its default had already been walked 0.5 → 0.25 → off before deletion.
  • Our Lab vibrance now has NO upstream counterpart (their vibrance is the density-space Dye Separation). Ours stays for sidecar compat and is identity in every parity config — recorded as a SwiftInvert-maintained control unless/until we converge on Dye Separation.

PORTED 2026-07-29 (same day, user approved) — items 1 and 2: Print Saturation (printSaturation, default 1.0, UI 0–2, derive clamp 0–3) and Dye Separation (dyeSeparation, signed ±0.5) landed through the full control checklist: settings + decoder + history labels (tripwire counts 48 → 50), derive passthrough, printCurve BOTH sides — after the toe softplus, on density above paper base, Print Saturation as the uniform-k mean-deviation reduction of NegPy's saturation matrix (identity dye matrix here; per-channel trims NOT ported, consistent with the recorded per-layer-trims skip), Dye Separation with the exact spread-sigmoid mask (2·σ(spread/0.4) − 1, sign selects the population; scale = K.dyeSeparationSpreadScale, MSL literal — new constants sync point). CurveUniforms grew via the ex-pad slot + a tail field (stride 256 → 272, pinned in LayoutTests). DensityChromaTests: identity at defaults, neutral invariance, k-direction on density spread, the sign-selects-population contract both ways, sidecar round-trip; the tone-controls GPU-parity case now runs with both active. No fixture re-dump (identity in every dump config; all 160 tests green incl. NegPy fixture parity). Bench steady-state unchanged (~4 ms/frame). Lab vibrance stays visible for now (its help text points at Dye Separation as the successor); hide/deprecate is a future UX call.

Still to port (proposed, not yet implemented): 3. Colour ring-around (b646e23, Shift+F) — the RA4 filtration proof: 5×5 mosaic of real renders stepping ±2cc in 1cc steps on magenta and yellow, absolute ladder centred on neutral; click a patch to keep its filtration; shares the canvas with the test strip. Pairs naturally with the carried test-strip port. 4. Test strip — PORTED 2026-07-29 (same day, user approved; revised 5×5 spec): TestStrip grid math + incremental mosaic assembly in NegativeKit (tiling/hit-test/nearest-rung/assembly all closed-form tested), ImageSession.renderTestStrip reusing the warm cache tower (one analysis, one source upload, 25 derive+renderDisplay passes, ~150–250 ms, never HQ), canvas presentation with upstream's rules (no gridlines, hovered-patch outline, bold axis labels, current-rung accent), Print-group button + ⇧T (key monitor, text-field-guarded) + Escape-clears-first. Click = one history entry setting density+grade; auto toggles untouched (patches were rendered under them); cleared by any edit/navigation/tool/baseline/HQ change, stale builds fenced by a generation counter. One documented presentation divergence: columns mirrored so the image BRIGHTENS left→right (our "right = brighter" slider convention; upstream draws density ascending). TestStripRenderTests pins the core invariant end-to-end on the GPU: every mosaic patch is byte-identical to a full render at that patch's settings. 167 tests green.

Noted, not proposed: 38aa023 step wedge (21-step transmission wedge printed through the frame's settings under their curve chart — tied to the H&D/Analysis panel we deliberately don't ship, same rationale as the density_histogram skip); 64b6e79/9b04748 grain-focuser loupe (2× unsmoothed loupe + acutance figure, preview/full-res badge — UI tool; the acutance read-out is the interesting fragment if we ever want a sharpness aid).

Not applicable: da9a033 contact-sheet tiles at proof scale (feature we don't ship), 717db98 hide _IR TIFF sidecars from the contact sheet (retouch/scan stack).

dump_fixtures.py: BROKEN ≥de79e13 — see the Last reviewed block; adapt the lab_color case before any re-dump past this range.

Still open (carried over): 91a1b78 tunable Auto Density/Grade targets (user-initiated only); the on-scan Color Mixer band re-tune pass (ours).

2026-07-28 — through e4bc450 (0.44.0 → 0.45.0, 6 commits)

Kernel status: untouched — no golden moves, no constants. The two features/exposure|process/ hits are additive UI-feature math and capture gating; dump_fixtures.py unaffected.

To port (proposed, not yet implemented — presentation layer, not pipeline): e4bc450 Test strip (0.45.0's headliner, Shift+T): the frame printed as a 6×6 grid of REAL renders — Print Density 0.4…1.9 in steps of 0.3 left to right, Grade R55…R180 in steps of 25 top to bottom — so the diagonals read light-to-dark and soft-to-hard like a split-filter test strip; click a patch to commit its density+grade. Design decisions worth keeping: ladders are ABSOLUTE (strips comparable frame to frame, both straddle the defaults inside slider ranges), Auto Density/Grade stay untouched on pick (the patches were rendered under them), always preview-res, session-only state cleared by any real edit, NO gridlines (reads as one print; only the hovered patch outlines), current-settings rung accented on the axis labels. Their new analysis.py helpers (strip_cells/strip_mosaic/strip_patch_rect/strip_cell_at/ strip_nearest_cell) are pure grid math — a Swift port is app-layer: 36 derive+renders at preview size is ~150–250 ms here (our slider path is ~5 ms/frame), one mosaic texture or 36 draws, hit-test + commit. No parity surface, no fixture re-dump. Moderate effort (~half day).

Not applicable: 6073a98 sensor-profile gating when linear raw is off (crosstalk/capture stack), 44f2a74 BEFORE-badge sync (their compare UI), d06f45f auto-crop rebate + Rebate Trim (their camera-scan auto-crop detection; we ship none), 9ef7732 settings-picker default-values fix (their preset picker), acf9ca5 IR-removal mottling on noisy IR planes (retouch).

Still open (carried over): 91a1b78 tunable Auto Density/Grade targets (user-initiated only); the on-scan Color Mixer band re-tune pass (ours).

2026-07-27 (second) — through 31aea5c (0.44.0 release, 5 commits)

Kernel status: untouched — no golden moves, no constants, no parity impact. The one features/exposure/ hit is additive measurement math for a UI feature (below); dump_fixtures.py unaffected (its density_histogram import is signature-stable).

PORTED 2026-07-27 (same day, user approved): ae56f8b Zone system overlay — ZoneGrid (NegativeKit: grid + flood-fill region labels, closed- form tests incl. stride padding, concave-anchor and densitometer-ruler agreement), ZoneOverlay (SwiftUI Canvas: merged-region edges with dark underlay, bold numerals, paper ends red), computed from DensitometerState's cached bytes per adopt/toggle, gated to the plain presentation like the probe. Toggle: "Zones" control-bar button + View menu + ⇧Z — implemented in the window key monitor with a first-responder text guard (a bare-letter menu equivalent would fire while typing; lesson from the profile-name field). Deviation from upstream, documented in code: integer-boundary box means instead of INTER_AREA (differences sit under the zone rounding step; no parity surface). 147 tests green. Original proposal, for the record: integer Adams zone per cell of a fixed grid (24 cells along the long edge) computed from the display-encoded frame via area-average downsample (the averaging damps grain — no extra smoothing); contiguous same-zone cells merge into regions (shared edges simply not drawn), one bold Roman numeral per region with the label anchor snapped to a cell the region actually owns (a concave region's centroid can land outside it), paper black (0) and white (X) flagged red, dark underlay beneath the grid lines for readability over blown highlights; built once per render so toggling costs a repaint. Crucially it reads the SAME zone ruler as the sidebar zone strip and spot densitometer ("the three never disagree") — which we already ported (Densitometry.zone(ofEncoded:) over the displayed rgba8 bitmap, cached in DensitometerState). A Swift port is pure app-layer: grid + tiny connected-components over a ~24×16 int grid (no OpenCV needed), a SwiftUI canvas overlay, and a toggle; no parity surface, no fixture re-dump. Moderate effort (~half day incl. the pinned-to-picture pan/zoom mapping).

Not applicable:

  • f7f3972 chroma denoise edge-bloom fix (taps weighted by chroma similarity as well as distance; slider renamed Chroma Denoise) — lab denoise stage we don't ship. Divergence note updated: if denoise is ever implemented, port THIS edge-aware version.
  • b9b98c3 DNG export dropped + config-migration centralization (their export formats/config plumbing; we never offered DNG),
  • a8027af thumbnail-cache clear in Manage Database (their DB tooling),
  • 31aea5c release chore. (0.44.0 changelog's remaining entries — Dye Mute 0.25, glow/halation luma, paste re-meter, filed-carrier flare — were all reviewed in the two prior entries.)

Still open (carried over): 91a1b78 tunable Auto Density/Grade targets (user-initiated only); the on-scan Color Mixer band re-tune pass (ours).

2026-07-27 — through 9722a9c (0.43.0 → 0.43.1+, 6 commits)

One golden move, and it's inside a recorded skip: 6fd61c5 lowers the Dye Mute default 0.5 → 0.25 (lab/models.py chroma_damping; relocation goldens regenerated — "less chroma damping on the default look"). This is the divergence baseline moving TOWARD us: upstream themselves flagged the 0.5 default as tuned on the old ProPhoto gamut (2026-07-20 review) and have now halved it, walking their canonical look halfway back to our no-damping position. Skip stands, reinforced; reopening condition unchanged (visible oversaturation at hard grades on real rolls) — and if Dye Mute is ever ported, the reference default is now 0.25. Our fixtures are unaffected (damping is derivation-side and no dump config exercises it); dump_fixtures.py signatures unaffected.

Not applicable (each checked):

  • 3ca00f2 glow/halation luma → Adobe RGB weights (0.2974/0.6273/0.0753): fixes ONLY the glow/halation taps in features/lab/ (stage we don't ship). Verified the core analysis luma upstream is still Rec.709 (domain/types.py LUMA_R 0.2126 at the tip) — so our K.lumaR/G/B mirror remains correct for the uses we ported (bounds/meters/histogram/ densitometry). Worth remembering if we ever add a halation-class effect: luma taken on WORKING-encoded triplets must use working-space weights.
  • 5a00dd9 re-meter when pasted settings change the analysis region — their paste can transfer the region; ours structurally can't (analysisRect is in the keepingGeometry list, never pasted), so the bug has no counterpart here.
  • 0a9d22a slider commit baseline on external sync (their Qt settings-db plumbing), f783fd0 0.43.1 release chore, 9722a9c filed-carrier bevel flare + paper margin + 2-D edge roughness (print finishing, out of scope).

Still open (carried over): 91a1b78 tunable Auto Density/Grade targets (user-initiated only — see 2026-07-26 note); the on-scan Color Mixer band re-tune pass (ours, post-b3490eb).

2026-07-26 — through 0e5b3f6 (0.43.0 tail, 4 commits)

Kernel status: untouched — a genuine null. The path-filtered log over features/exposure/, features/process/, kernel/image/ and the characterization goldens is empty; no renames; no VERSION/CHANGELOG movement. The one render-adjacent hunk was read in full: desktop/workers/render.py (+5) adds a separate Qt signal so a batch thumbnail overwrite can't clobber an already-rendered canvas frame — their worker plumbing, zero kernel lines. No fixture re-dump, no constants drift, dump_fixtures.py unaffected.

Ported: nothing (nothing required).

UI idea worth noting (not pipeline): e5f99ff slider UX — their Qt CompactSlider now grabs on click anywhere in the groove (absolute jump, Shift = relative fine-drag) and forwards near-miss clicks in an ~8 px band above/below the groove into a real drag. Our SwiftUI sliders already click-to-jump; the near-miss band + Shift-for-fine-drag are candidates if slider precision ever comes up.

Not applicable: 9319408 camera live-view ability checks (capture), 00d01c3 RGB-triplet thumbnail rendering (their thumbnail service; camera-RAW only here), 0e5b3f6 macOS release CI (their packaging).

Still open (carried over): 91a1b78 user-tunable Auto Density / Auto Grade targets — the "needs a Settings surface" blocker is weakening now that the app has the profile picker/editor windows (2026-07-25), but those manage ADJUSTMENT profiles; tunable targets are analysis CONSTANTS (anchor/grade calibration), a different layer. Note the adjacent history: an anchor-meter recalibration A/B for these same constants was built and dropped 2026-07-25 (user: don't pursue) — any tunable-targets port should be user-initiated. Also open: the on-scan Color Mixer band re-tune pass (ours, post-b3490eb).

2026-07-25 — through 0369b10 (0.42.0 → 0.43.0, 14 commits)

Kernel status: ANALYSIS SEMANTICS MOVED UPSTREAM — goldens regenerated. One commit, 127bcd7 ("Improve cast-removal estimators and fix chart cast parity", 0.43.0's headliner), rewrites the two analysis estimators we ported, with test_scene_linear_relocation.py goldens moved (small deltas ~1e-3 on the synthetic scene — it has no strong cast; the point of the change is real scans WITH casts). No WGSL/shader changes anywhere in the range — this is CPU-analysis only, so a port touches NegativeKit + fixtures, not the Metal side.

PORTED 2026-07-25 (same day, user approved and chose it as the default) — 127bcd7, all pieces together as one semantic unit. Landed in Meters.neutralAxis (two-pass rewrite), BoundsAnalysis.samePixelColorFloorRefs

  • analyze wiring, K (six constants), and Stats [Double] overloads (np-matching percentile/median — the same-pixel path is float64 end-to-end like upstream, bit-comparable arithmetic). The vestigial analyze(channelsSorted:) public overload was folded away (offset re-derives stopped re-running analysis at 2125a34; nothing external used it). Fixtures re-dumped from 0369b10; all 132 tests pass, including AnalysisParityTests/GridParityTests against the new-estimator fixtures. Branch coverage verified positively: the same-pixel branch FIRES on synthetic_grid (refs ≈0.1D off the percentile floors, Swift matches) and correctly falls back on synthetic64; the two-pass axis moves synthetic64's confidence 0.984 → 0.337 (the n/(n+256) size term bites on a 32×32 grid — real previews sit near 393k grid px, where it doesn't). Real-scan A/B (three CR3s, negcli meter old vs new binary): neutral-rich frames move ≤0.004D; IMG_0365's bright probe went 0.768/0.785/0.791 → 0.789/0.784/0.777 — a slightly cyan highlight now reads neutral, the exact failure mode the same-pixel floors target. An independent line-by-line Python↔Swift audit cleared all eight semantic areas and surfaced two last-ulp fidelity gaps, both fixed: Stats.percentileOfSorted now mirrors numpy's two-sided _lerp (interpolates from the upper bound when frac ≥ 0.5 — both overloads), and the neutral axis's pass-1 luma/chroma read the ROUNDED float32 norm values (upstream computes them from the float32 normalized image). The audit's remaining note (two guards invert only under NaN) is unreachable: the grid is log10(clip(...)), finite by construction. Bench: slider path unchanged (4.6 ms/frame); prepare 157→182 ms, finalize 25→47 ms (per-image analysis, matches the added work). CLAUDE.md §2 + the constants-sync paragraph updated.

The pieces, for the record:

  1. Hue-uniform chroma metric: near-neutral ranking switches from max−min to pairwise RMS sqrt(((r−g)²+(g−b)²+(r−b)²)/3) — max−min scores an opposed R/B split double a same-side deviation. Used by both estimators below. Maps to our finalize neutral-axis band selection.

  2. Two-pass neutral axis (measure_neutral_axis_from_log): pass 1 selects under a LOOSE cap (neutral_axis_first_pass_cap 0.55 — admits strong-but-correctable casts the old single 0.35 cap rejected outright; saturated content still fails); the affine R/B→G correction implied by pass-1 mid+shadow refs (normalized space) re-ranks chroma; pass 2 selects true neutrals under the strict cap, now 0.29 (was 0.35).

  3. Confidence rebuilt: tight × size × agreement — tight = 1 − max(midChroma, shadowChroma)/cap on CORRECTED chroma (was mid-only, uncorrected); size = n/(n+256) (neutral_axis_confidence_n0); agreement = 1 minus the mid↔shadow R/B deviation-difference beyond a 0.10 dead zone, rolled off over 0.20 (neutral_axis_agreement_deadzone/ _scale). Drives our strength = confidence × slider directly.

  4. Same-pixel colour floors (_same_pixel_color_floor_refs + analyze_log_exposure_bounds_from_log wiring): the colour axis's dense end (print whites) now reads ONE shared chroma-gated pixel set — the luma-extreme percentile band [colorClip, colorClip+4] (color_bounds_band_width 4.0), chroma measured base-anchored (offsets from the thin-end refs, per-channel span as provisional gamma, refined once from band medians, same two-pass loose/strict caps) — instead of independent per-channel percentiles, so coloured highlight content stops masquerading as film cast. Falls back to the percentile pass when the band holds no trustworthy neutrals. The thin end stays percentile-based (film density is bounded below by base). Maps to BoundsAnalysis.analyze's colour axis.

    New K constants: neutral_axis_chroma_cap 0.35→0.29, neutral_axis_first_pass_cap 0.55, neutral_axis_confidence_n0 256, neutral_axis_agreement_deadzone 0.10, neutral_axis_agreement_scale 0.20, color_bounds_band_width 4.0. All CPU-side (no MSL duplicates). dump_fixtures.py verified compatible before the re-dump — every imported symbol's signature is unchanged at 0369b10.

Not applicable:

  • 127bcd7's chart-parity half: cast_solve_inputs (single source of truth for CPU processor + chart — our deriveRenderParams already IS that), CharacteristicCurve gaining curvature (chart-only class; their render path apply_characteristic_curve always had it, as does our ReferenceCurve), GPU engine exporting raw cast refs (chart plumbing).
  • ab5a6ad sensor-crosstalk calibration: 3×3 CFA unmix on the linear capture for single-shot narrowband-LED camera scans, calibrated from bare- light exposures, default None, gated off for RGB-triplet composites — capture-side crosstalk stack we don't ship. Noted for the crosstalk thread: upstream now formally splits sensor crosstalk (linear domain, pre-inversion, per-setup) from dye crosstalk (density domain, Density Mixer) — the planned negcli chart-solve is on the dye side and remains a SwiftInvert-original.
  • 8a1a3e1 selectable scanner backend, 6cea8a5 live-view drop/output- folder guards (capture stack); d7e2502 IR sidecar case-insensitive matching (retouch); 59e5352 DMG target-arch build flag (their packaging); 6e294fa/d7ca80c/5a9cc2d/9b2345a/91cac6d docs, 76ae85f/f85877b changelog, 0369b10 lint.

Still open (carried over): 91a1b78 user-tunable Auto Density / Auto Grade targets (blocked on a Settings surface); the on-scan Color Mixer band re-tune pass (ours, post-b3490eb).

2026-07-23 — through 07dd965 (0.41.0 → 0.42.0, 7 commits)

Kernel status: untouched — a genuine null. The path-filtered log over features/exposure/, features/process/, kernel/image/ and the characterization goldens is empty; no renames in the range; the full diff --stat touches only desktop/Qt, presets, contact-sheet and export-form code. The one rendering-adjacent hunk was read in full: services/rendering/image_processor.py (+18) is the contact-sheet tile downsampling fix (fdf43b7) — memory management in a feature we don't ship, zero kernel lines. No fixture re-dump, no constants drift, dump_fixtures.py unaffected. Changelog: 0.41.0 finalized + 0.42.0 opened, all entries UI/workflow/export-plumbing.

Ported: nothing (nothing required).

UI ideas worth copying independently (not pipeline):

  • ec66499 per-setting copy/paste + apply-to-roll: pasting opens a picker listing exactly the settings that differ on the source frame, grouped by section with values shown; per-frame geometry never overwritten. Our Copy/Paste Adjustments (⇧⌘C/⇧⌘V) is all-or-nothing (geometry excluded) — the granular picker is the natural upgrade if multi-frame workflows grow.
  • 1dcccbe presets redesign builds on the same picker (a preset stores exactly the ticked settings, applied as overlay or replace) — relevant only if we ever grow presets.

Not applicable: fdf43b7 contact-sheet tile memory (feature we don't ship), 4772dcd export-destination-mode restore (their export form; our exportOptions JSON blob round-trips the destination already), 07dd965 print-border tool-coordinate compensation (we ship no print borders, and our coordinate space is unified by baking orientation into pixels), 5e08828/650cf4b changelog/lint/skill churn.

Still open (carried over): 91a1b78 user-tunable Auto Density / Auto Grade targets (blocked on a Settings surface); the on-scan Color Mixer band re-tune pass (ours, post-b3490eb).

2026-07-22 — through a9e5169 (0.39.0-dev, 3 commits)

Kernel status: untouched — a genuine null. The path-filtered log over features/exposure/, features/process/, kernel/image/ and the characterization goldens is empty; no VERSION/CHANGELOG/PIPELINE.md movement. No fixture re-dump, no constants drift, dump_fixtures.py unaffected.

Not applicable (all three, each diff checked):

  • a9e5169 ICC tagging fixes across export formats — read in full because export tagging is a shared bug class, but all four defects live in features we don't ship: greyscale JPEG/WebP CMS (B&W), ACES/XYZ export targets (rawpy decode spaces; our export offers only sRGB/Adobe RGB), untagged contact-sheet JPEGs. Our ImageIO path tags from the CGImage's colorspace and can't produce the swallowed-lcms-error untagged case.
  • 40f7d2f toolbar streamline + compare/flat-peek stabilization — Qt UI. Their fix (rotate/flip re-render INSIDE an active compare view via rerender_active_view instead of dropping to the plain edit) doesn't map: our baseline compare is hold-to-press (showingBaseline), so geometry ops can't interleave with it, and we have no flat-peek.
  • 1d48e01 stitch-config sidecar-key whitelist warning — scan stitching, capture side.

Still open (carried over): 91a1b78 user-tunable Auto Density / Auto Grade targets (blocked on a Settings surface); the on-scan Color Mixer band re-tune pass (ours, post-b3490eb).

2026-07-21 — through 8d6f44e (0.39.0-dev, 21 commits)

Kernel status: untouched — a genuine null. The path-filtered log over features/exposure/, features/process/, kernel/image/ and the characterization goldens is empty; no renames in the range; the pipeline-tree diff is empty. No fixture re-dump, no constants drift, dump_fixtures.py unaffected. The range is film-scanner integration (Coolscan/SANE bba487d, RGBI + IR dust over SANE 8d6f44e), IR dust reconstruction rework (f612a74), lab sharpen improvements (d3436c7 — stage we don't ship), multi-part scan stitching (5e141df — capture-side composite assembly), contact-sheet/DB/UI work, and docs churn.

Noted for the active crosstalk thread (not a pipeline change): a27f035 widens the crosstalk matrix adjustment range in their EDITOR dialog by one line — the matrix math is untouched. Confirms the Density Mixer remains manual upstream; the chart-based auto-solve being planned here (negcli chart-solve, see 2026-07-20/21 conversations) stays a SwiftInvert-original with no upstream counterpart to converge with yet.

Not applicable: 2d8e55e TIFF sRGB decode gating (their TIFF ingestion; we're camera-RAW only), 67e2051 scan-window exposure gating, ce28dc1 DB dialog, 9c260e2 contact-sheet labels, 2cdc569 filmstrip thumbnails, b805578 icon/migration fixes, readme/changelog/tutorial commits.

2026-07-20 — through 2cdc569 (0.39.0 → 0.40.0, 9 commits)

Kernel status: untouched. Zero commits in the range touch features/exposure/, features/process/, kernel/image/, or the characterization goldens — the path-filtered log AND git diff --stat over those trees are empty, and there are no renames in the range (--diff-filter=R empty). The shared-kernel-adjacent hunks were checked by hand: lab.wgsl + lab/logic.py/models.py changed ONLY the sharpen block (rewritten for the 0.40.0 sharpening feature — zero lines touch vibrance/ saturation/Dye Mute or the Lab matrices our colorPop mirrors), and the domain/models.py hunks are sidecar migrations for features we don't ship (IR inpaint radius, filed-carrier toggle fold). No fixture re-dump, no constants drift; dump_fixtures.py signatures unaffected (exposure normalization.py/logic.py unchanged).

Ported: nothing (nothing required).

Divergence baseline moved (no action): d3436c7 rebuilt sharpening — Method selector (Unsharp Mask with halo-suppression overshoot clamp + gradient Masking, or Richardson-Lucy deconvolution on linear Y applied as a chroma-preserving RGB ratio), Radius/Masking sliders, preview/export parity via shared gaussian_kernel_1d taps (the old fixed 5×5 GPU kernel sharpened the wrong band at export scale). We don't ship sharpen (recorded divergence); if it's ever implemented, port THIS version (PIPELINE.md §5.4 documents the full math). Default sharpen stays 0.25.

Noted upstream self-doubt on Dye Mute (strengthens our skip): PIPELINE.md now carries "(The default was tuned against the old ProPhoto working gamut — it may run strong now that the working space is Adobe RGB.)" — upstream themselves flag the 0.5 default as possibly too strong post- b3490eb. Our 2026-07-17 skip stands; reopening condition unchanged (visible oversaturation at hard grades on real rolls).

UI idea worth copying independently (not pipeline): b805578's analysis-region active-indicator — a small dot on the Freedraw Analysis Region button whenever a custom region is overriding the buffer. We have the same override semantics (resolve_analysis_region port) and the same discoverability gap after the tool closes.

Not applicable: a27f035 crosstalk matrix range (stage we don't ship), bba487d Coolscan/SANE film scanning (capture stack), f612a74/8a98326 IR dust reconstruction (retouch; runs pre-normalization on IR-carrying scans — we're camera-RAW only, no IR plane), d3436c7's non-sharpen bulk (their GPU engine sharpen-pass plumbing), c3e83ff tooltips, b805578's icon fixes/carrier migration, c53aa26 USER_GUIDE rewrite, 2cdc569 filmstrip thumbnail fixes.

Still open (carried over): 91a1b78 user-tunable Auto Density / Auto Grade targets — blocked on us growing a Settings surface; the on-scan Color Mixer band re-tune pass (ours, post-b3490eb).

2026-07-19 — through 96adfde (0.38.0 → 0.39.0-dev, 19 commits)

Seven pipeline-relevant commits — the deepest range since the original port, headlined by a full working-space swap.

The headline: b3490eb Adobe RGB (1998) working space. Upstream REVERSED the 2026-07-16 ProPhoto output fix: full ProPhoto primaries at output are now judged "unnaturally saturated, pain to correct", and the whole pipeline boundary moved to Adobe RGB — OETF ROMM TRC (1.8 + linear toe) → pure 563/256 gamma (no linear segment), output tagging, Lab matrices, CLAHE/toning shaders, display/export management, ALL goldens regenerated. Dye Mute stays at default 0.5 on top, so their canonical look is now markedly more muted than either the pre-fix or the ProPhoto-era look. Third output-space change in four days (stale Adobe RGB bug → ProPhoto

  • Dye Mute → deliberate Adobe RGB).

Judgment (revised 2026-07-20 after researching issue #537 / PRs 518/538/544): the "third change in four days" framing was wrong — this is NOT a flip-flop. NegPy's output had been Adobe-RGB-interpreted for its whole life via a stale tag; PR #518 exposed true ProPhoto for the first time, two independent users immediately reported neon reds AND hue shifts (red→magenta, sky→cyan) with image evidence, Dye Mute could damp chroma but not hue, and #544 restored Adobe RGB coherently (primaries + pure 563/256 TRC + D65) within three days. The argument (user thetalkingdrum, adopted verbatim by the maintainer): the pipeline ASSIGNS primaries to raw uncharacterized sensor RGB at output — an interpretation, not a conversion — and ProPhoto's imaginary green/blue primaries stretch dye separations outside the spectral locus. Decision is settled upstream (both reporters confirmed the fix; follow-ups are routed to crosstalk characterization).

The argument applies to SwiftInvert verbatim — we tag sensor-native pipeline output as ROMM the same way — and one of our own divergences may be evidence: redHue +0.5 exists because "C-41 reds skew magenta out of the box", which matches the reported ProPhoto-interpretation hue shift exactly. A correct-primaries output might let redHue return toward 0. PORTED 2026-07-20 — the user chose convergence over A/B ("I want to stay close to the main project"). Full port: WorkingOETF → pure 563/256 gamma (Swift + MSL 0.45470693 literal), Lab matrices/white → Adobe RGB D65 both sides, output tagging → adobeRGB1998 (ImageConversion, ColorIO workingColorSpace, negcli TIFF), littleCMS oracles regenerated from NegPy's AdobeCompat-v4/sRGB-v4 at 96adfde, fixtures re-dumped from 96adfde (dump script adapted to the paper_black rename, manifest key stable), coupled constants ported (anchor 0.75, grade target 0.6, strength 0.5). Space-sensitive tests recalibrated with intent preserved: True Black's contract restated in the linear domain (the old encoded thresholds baked in the ROMM toe), pre-saturation chroma margin 1.05 → 1.02 (smaller-gamut Lab), mixer-band test pixel moved in-band (real- content blues land 240–265° in the new Lab — the band constants themselves survive). ExportColorSpace's wide option relabeled Adobe RGB (case name kept for sticky-JSON compat). Export-note: existing exports re-render slightly different, as upstream's changelog warns. Follow-ups: redHue +0.5 RETIRED same day (it countered the hue skew this port removes at the root; default 0 again, explicit sidecar values preserved); the on-scan mixer-band re-tune pass remains open. 132 tests green incl. GPU parity against Adobe-world fixtures; bench unchanged.

Coupled to the above — do NOT port separately: 2db0470 + 088c393 auto-constant tunings (anchor_target_density 0.74 → 0.75, auto_grade_target 0.55 → 0.6, auto_grade_strength 0.3 → 0.5, goldens moved). These were tuned against the Adobe RGB output; applying them under our ROMM output applies their new-space taste to our old-space look. Port together with b3490eb or not at all.

Ported (2026-07-20) — we shared the bug: 2125a34 Cast Removal neutral axis vs PRE-trim bounds. Their CPU measured the neutral axis against user-trimmed (WP/BP-adjusted) bounds while their GPU measured pre-trim; they standardized on pre-trim ("the film's inherent cast is a source property — creative trims shouldn't perturb it"). Our finalize had faithfully ported the now-declared-buggy CPU side. Ported as the simplification it implies: finalize/analyze lost their offset params (the analysis is now fully offset-independent; offsets fold into finalBounds at derive time only), ImageSession's second cache tier (AnalysisKey) dissolved — wp/bp handle drags re-run no analysis at all — and ImagePipelineSeamTests pins the new semantics (axis == base-bounds measurement; offsets still reach the render). Fixtures unchanged (all dump configs use zero offsets); CLAUDE.md §2 updated.

To port (proposed, needs a Settings surface + the visible-improvement bar): 91a1b78 user-tunable Auto Density / Auto Grade targets — app-global calibration (TUNABLE_TARGETS ranges over 5 anchor/grade constants, Set Targets dialog, TARGETS_REVISION cache-bust). The right shape for per-scanner calibration; we have no Settings window yet (TODO).

Bookkeeping (no action): 687bcd5 True Black renamed Paper Black, inverted — new default (off) keeps BPC on, so upstream's effective default still matches ours; only nomenclature/polarity changed. Our trueBlack field and UI naming stand; renaming to match upstream is a cosmetic option, recorded here so the next review doesn't re-derive the polarity mapping (paper_black = !bpc).

Not applicable: 81bea3c half-frame mode (their asset/session model), 4678569/96adfde camera-scanning fixes, 7e888ef dodge/burn mask visibility, 13a7ba5/3113241 update banner, b14dc62 tutorial, docs/changelog/roadmap churn (a11535f 18f6dd5 7a0046d 46c85c2 c27b379 5bd0c03 57948f5 0ca43de-style lint).

dump_fixtures.py: BROKEN against ≥b3490eb — _oetf_encode_flat/ _oetf_decode_flat lost their break-point parameters and the OETF semantics changed; the closed-form working_oetf fixture case would dump Adobe-gamma values against our ROMM oracle. Verify/adjust the script BEFORE any re-dump past b3490eb (it still works at ≤6b841a1 checkouts).

2026-07-17 — through 0ea27d2 (0.38.0 tail, 6 commits)

One pipeline-relevant commit, and it's a golden move: 8bc9678 Dye Mute — grade-coupled chroma damping, ON by default upstream (0.5), relocation goldens regenerated. Mechanism: damp = (slope_min/slope_g)^strength (green reference slope, clamped) folded into the Lab saturation multiplier at parameter-derivation time — per-channel print curves multiply channel separation by the slope, so chroma inflates with grade; the damping counters it ("mimicking paper dyes' unwanted absorptions"). No WGSL/uniform change upstream; the identical fold works here (colorPopActive reads derived params, so params.saturation × damp self-activates the pass). Port cost ~15 lines + tests, NO fixture re-dump (derivation-side; apply_saturation unchanged). dump_fixtures.py signatures unaffected (new function only).

Deliberately skipped (for now) — reopening condition recorded: Dye Mute is not ported despite being a golden move. Their motivation was a regression fix: the ProPhoto output bug had been squeezing their gamut for releases; fixing it (07e3f8f) suddenly exposed full-gamut chroma their users never saw, reading oversaturated at hard grades. We never had the bug — our color has been full-gamut ProPhoto from day one, and our deliberate divergences (preSaturation 1.15, redHue +0.5) were A/B-tuned ON that gamut toward MORE color, not less. Adopting their 0.5 default would desaturate our established default look ~15% at typical grades (up to ~55% at slope 10); adopting the slider at 0 would add exactly the kind of dormant control the 2026-07-16 removals just cleared out. Reopen if hard-grade frames ever visibly oversaturate on real rolls — the mechanism above is the ready-made fix, and one negcli A/B decides the default.

Also in 8bc9678: default lab sharpen 0.5 → 0.25 (we don't implement lab sharpen — divergence note updated in CLAUDE.md).

Not applicable (this range): 5811662 crop-ratio picker consolidation (their UI; NOTE their final ratio list — 7:5, 16:9, 16:10, US Letter — as reference for our own TODO'd aspect presets), 611b251 Finish/geometry sidebar cleanup + auto-narrowband-on-RGB-scan (capture-side scanning stack), 0ca43de lint, 1c07529 tooltips, 0ea27d2 changelog. Changelog-only item: "Cast Removal strength sticks across frames" is their session-sticky settings model — ours is per-image sidecars + explicit Copy/Paste, an architectural divergence, not a gap.

2026-07-16 — through 4a669ed (0.38.0 → unreleased, 9 commits)

Kernel status: untouched. Zero commits in the range touch features/exposure/, features/process/, kernel/image/, or the characterization goldens — the path-filtered log is empty, git diff --stat over those trees returns nothing, and there are no renames in the range (--diff-filter=R empty). A genuine null for the inversion pipeline: no fixture re-dump, no constants drift, dump_fixtures.py signatures unaffected. The one shared-kernel-adjacent hunk was checked by hand: lab.wgsl changed only a stale comment ("Adobe RGB" → ProPhoto/D50 — the code fix was 07e3f8f, reviewed 2026-07-15), and the lab/logic.py rewrite is entirely the CLAHE function; vibrance/saturation (mirrored by our colorPop) are untouched.

Ported: nothing (nothing required).

Not applicable (this range):

  • 232f26d unify CPU/GPU CLAHE into one Lab-L algorithm (+ new test_gpu_curve_parity CLAHE case, PIPELINE.md now documents CLAHE as its own stage before Retouching) — local-contrast lab stage we don't ship. If we ever add local contrast, port THIS version (fixed 8×8 tile grid, 256 bins, integer-count clip + even redistribution, smoothstep-bilinear CDF blend on CIELAB L*, CPU/GPU pinned to ~1e-6).
  • c714a24 Feat/finish — Finish panel: edge burn (true exposure burn in stops, radial↔rectangular roundness), filed-carrier black rebate, print mats — print-finishing stage, out of scope. The edge burn design (stops-domain I·2^(−s·m), card-burn roundness) is the note-worthy idea if a vignette tool is ever wanted.
  • 78b74ef roll-aware Auto Crop All + consensus detection (~500 lines in geometry/batch_autocrop.py + big geometry/logic.py growth) — camera-scan auto-crop detection; we have no auto-crop detection feature.
  • 16bcee8 DNG/JXL export via imagecodecs 16-bit CMS — their export CMS stack; we export JPEG/TIFF through ImageIO/ColorSync.
  • 4a669ed export_fmt/color_space override in all_saved scope — their export-preset session plumbing.
  • 2682a0a camera-scanning calibration fix; 69a2934 status toasts / crop busy overlay; ca18ecb overflow-menu fix; 86e73ba changelog — UI/capture.

2026-07-15 (second review) — through 6b841a1 (0.38.0 tail, 9 commits)

Kernel status: DEFAULT LOOK MOVED UPSTREAM. Three commits (0f063cc, 67b5a8c, 6b841a1) changed exposure/models.py and regenerated both characterization goldens — the highest-priority signal this log tracks. Net change at the tip (0f063cc bounced auto_grade_target to 0.6, 67b5a8c back to 0.5, 6b841a1 settled it):

  • paper_dmin default True → False (paper white d_min 0.06 → 0; highlights print brighter — goldens moved 0.86 → 0.94 in the lights).
  • true_black default False → True — upstream converged on OUR recorded divergence. No code change here; the CLAUDE.md divergence entry ("trueBlack default on; NegPy ships it off") is now stale and should be dropped when the port lands.
  • EXPOSURE_CONSTANTS["auto_grade_target"] 0.5 → 0.55, ["auto_grade_strength"] 0.4 → 0.3 — Auto Grade targets slightly higher contrast and adapts less to scene range. Maps to K.autoGradeTarget / K.autoGradeStrength (ExposureConstants.swift:67-68), CPU-only (no MSL duplicate). Also shifts CurveLogic.defaultGradeRange 1.0 → 1.1, the denominator of the Negative-character read-out — upstream's stats._negative_row uses the same default_grade_range(), so porting the constant keeps that diagnostic in lockstep automatically.

Ported (2026-07-15, same day as the review):

  1. K.autoGradeTarget 0.5 → 0.55, K.autoGradeStrength 0.3 (ExposureConstants.swift — CPU-only, no MSL duplicate). Shifts CurveLogic.defaultGradeRange 1.0 → 1.1, which the Negative-character read-out tracks automatically (verified via negcli meter on a real CR3: "density range 0.958 default grade range 1.100 → normal").
  2. ExposureSettings.paperDmin default true → false, including the sidecar decoder fallback (user's call: no existing edits worth preserving, so no split-default dance). negcli meter confirms the paper floor is gone — brightest tone reads D 0.00 (was 0.06 = K.dMin).
  3. trueBlack: no code change (already our default); the CLAUDE.md divergence bullet is retired — it's upstream's default now too.
  4. Fixtures re-dumped from 6b841a1. dump_fixtures.py now records true_black in the per-config manifest (it already recorded paper_dmin), and both parity harnesses (AnalysisParityTests.settingsFrom, GPUParityTests.settings) read it instead of hard-coding the old NegPy default — future default flips on either side can't silently skew parity. Drift-catcher mutation lists (SidecarCodecTests, HistoryLabelTests) updated for the new paperDmin default. All 132 tests pass; negcli bench unchanged (4.4 ms/frame, prepare 157 ms, finalize 25 ms).

Deliberately skipped:

  • Lab sharpen default 0.25 → 0.5 + the lab.wgsl sharpen rework (0f063cc: real CIELAB L*-space unsharp mask with reflect-101 borders, sigma tracking scale_factor, smoothstep noise gate — replacing the old gamma-luma RGB-ratio scale). We don't ship sharpen (recorded divergence). Divergence baseline moved: if sharpen is ever implemented, port THIS Lab-space version, not anything older.

Not applicable (this range):

  • f309982 cast-removal strength sticks across frames, 6e55a4a True Black sticks across frames — their Qt session's frame-to-frame settings carry-over; we have per-image sidecars + Copy/Paste Adjustments, no carry-over model.
  • 07e3f8f colour-manage from the working space, not Adobe RGB — their AppState.workspace_color_space was left at "Adobe RGB" when the working space moved to ProPhoto, skewing preview/export/thumbnails together. SwiftInvert has no such field: display tags rommrgb directly, export draws ROMM into an sRGB context; ColorIOTests oracles were generated directly from NegPy's bundled ProPhoto ICC (not through their AppState path), so they are unaffected. Their deleted detect_color_space_from_raw was never ported.
  • 936ff88 untagged scanner-TIFF loading (sRGB → linear scanner data), 34e9efe TIFF export via imagecodecs 16-bit CMS — scanner-TIFF input and their export CMS stack; we're camera-RAW only and export through ImageIO/ColorSync.
  • 3a0175c Feat/heal — retouch (out of scope); its rawpy_loader.py hunk is the VueScan/Adobe SubIFD LinearRaw scanner-DNG path, also out of scope (camera DNGs go through LibRaw unaffected).

2026-07-15 — through ecec2bb (0.37.2 → 0.38.0, 7 commits)

Kernel status: untouched. Zero commits in the range touch features/exposure/, features/process/, kernel/image/, or the characterization goldens — the path-filtered log is empty and git diff --stat over those trees returns nothing. No renames in the range (--diff-filter=R empty; all tracked pipeline files still present at the tip), so this is a genuine null, not a path-filter miss. No fixture re-dump, no constants drift, dump_fixtures.py signatures unaffected. 0.38.0 is entirely triage/UI/workflow work.

Ported: nothing (nothing required).

Closed since the last review (were in "To port", now shipped here independently of upstream):

  • Fine rotation + Straighten (7f4b7a7) — shipped as our unified Crop & Straighten mode (CropGeometry, commitFineRotation), a Lightroom-model design rather than upstream's reference-line tool.
  • "Enter confirms crop" (3961b4d) — shipped (fa5c890), plus Escape-cancel.

Correction to this entry (same day): the TIFF-compression item below was first logged as "confirmed still absent". That was wrong. TIFF compression has been implemented since a499904 — Exporter.swift sets kCGImagePropertyTIFFCompression = 5 (LZW), and its comment already records the deliberate LZW-over-Deflate decision (ImageIO's Deflate support is undocumented). The false "confirmed" came from a verification grep truncated by head -12, forty lines before the relevant code. Item closed, not open. Lesson for future reviews: never head-truncate an absence check — absence is exactly what truncation fabricates.

Closed (was carried over as "To port"; already shipped here):

  • TIFF export compression (fb4b7a7) — done at a499904 (LZW). Upstream's Deflate+predictor is a deliberate skip, not a gap: ImageIO won't reliably write Deflate TIFF. Do not re-raise without new evidence.

Ported (2026-07-15, same day as the review):

  • 77c8113 spot densitometer + zone strip → NegativeKit/Densitometry.swift (zone(ofEncoded:), printDensity(ofEncoded:), read(encodedRGB:), zoneRoman), SwiftInvert/Densitometer.swift + DensitometerReadout.swift, wired to a canvas hover in DetailView with the read-out in the control bar. NegPy-exact semantics, including luma-on-encoded before the OETF decode. Divergence from upstream, deliberate: the probe reads the displayed rgba8 bitmap (already ROMM-encoded) instead of a GPU metric — upstream needs density_hist.wgsl to feed their H&D chart; we have no chart, so a 120-bin GPU pass would have no consumer. density_histogram therefore not ported; revisit only if we ever build the H&D chart. Also skipped: the ΔD-above-base per-channel figure — it needs the source linear pixel + bounds, i.e. an actor round-trip into ImageSession per pointer move, for the negative-diagnostic half of the read-out. D + zone is the darkroom core; ΔD is a candidate if the round-trip proves cheap.
  • Negative character diagnostic → Densitometry.character(densityRange:) (NegPy's 0.80/1.25 gates and wording), shown under the Grade slider — the slider it's about. Reads analysis.baseBounds.luminanceDensityRange, verified to be the same norm_density_range upstream feeds both its curve and this diagnostic.
  • Both are pure measurement (no render path), so the parity fixtures are untouched and no re-dump was needed. 92 tests pass, including a new DensitometryTests suite of closed-form oracles.
  • Verified on real scans via a new negcli meter command: on three CR3s the brightest tone reads D 0.06 on every frame — exactly K.dMin, the paper white the pipeline targets — and the character gates fire correctly (0.902 → normal, 0.710 / 0.494 → flat).
  • Unverified: the hover interaction itself — verified by hand 2026-07-15: hovering the canvas meters correctly. (The original gap: synthetic mouse events can't reach the unbundled binary — no accessibility permission, app won't take focus from a shell — and the known-working histogram hover ignored them too, proving the harness was what failed. Lesson kept: GUI hover paths in this app need a human pointer to verify.)

New candidate (perf/architecture, not pipeline) — half ported, half declined:

  • 938fe9e "halve preview-load memory; instant frame switching". Ported: multi-frame retention — AppModel.sessionLRU keeps the 2 most recent ImageSessions (upstream's preview_cache_max_full_res_entries budget: active frame + the one navigated from), with releaseHQ() stripping the full-res tier from the frame that isn't on screen. Retention alone suffices here because every cache tier is already keyed. Declined: upstream's RenderMemo — it memoizes the last displayed render because their re-render is expensive. With the tower warm ours is derive+GPU (~5 ms), so a memo of the CGImage would add a staleness surface (their key has to track HQ flag, working space, GPU engine, soft-proof ICCs, monitor profile) to save 5 ms. Not worth it. Declined: copy elision — their win was deleting numpy defensive .copy() calls. Swift arrays are COW, so we never had that class of waste; the one place it would matter is already explicit (preview = meterPreview at 0°, commented "COW: at 0° the render input IS the meter image, no copy"). No change made. Original analysis of both ideas, retained for context:
    1. Multi-frame retention. Upstream gives full-res cache entries a slot budget (default 2: active frame + the one navigated from) so navigate-back is instant, and memoizes each frame's last displayed render in a new RenderMemo keyed by config + every display-path input, painting from it immediately while the authoritative render refreshes underneath. We hold exactly one ImageSession (AppModel.swift:506 reassigns a single optional), so navigating back drops the entire cache tower — decode, oriented preview, Prepared (~150 ms), textures — and rebuilds from scratch. A 2-slot session LRU would be the bigger win for us than the memo itself, since we discard more than they do. Wants a memory-budget check first (our HQ path already caches a full-res decode per session).
    2. Copy elision under a read-only contract. They removed three redundant full-size buffer copies (peak RSS 2880→1609 MB on a 56 MP load) by letting cache and caller alias one buffer. Less directly applicable — our RGBImage copies are value-semantic and our contract already forbids handing out live textures — but worth a look at the HQ decode path if HQ memory ever becomes a complaint.

Not applicable (this range):

  • 976851c UI refinements; ecec2bb panel pin/reset docking; 979b592 adaptive canvas-toolbar overflow — their Qt dock/panel layer.
  • 13b9434 heal/scratch edits never persisted — retouch, not shipped here.
  • 2079d7c docs (their CLAUDE.md slim-down); 0ca292d CI self-assign workflow.
  • 0.38.0 changelog headliners we don't ship: Keep/Reject contact-sheet triage, unreadable-file badges, roll-wide undo, canvas-tool Esc grammar, colour/ Filtration renaming. One idea worth noting even though the feature is out of scope: their two-stage Esc (first clears in-progress points, second puts the tool down) — our Escape already cancels Crop & Straighten wholesale, which is the right behaviour for a mode with no in-progress point list.

2026-07-14 — through 0500404 (0.37.1–0.37.2, 7 commits)

Kernel status: untouched. No commits in the range touch features/exposure/, features/process/, kernel/image/, or the characterization goldens — no fixture re-dump, no constants drift, dump_fixtures.py signatures unaffected.

Ported: nothing (nothing required).

Not applicable (this range):

  • 2ecaebb GPU readback-vs-destroy race fix (per-texture lock in their wgpu GPUTexture; densitometer hover on the UI thread raced engine cleanup on file switch). SwiftInvert's architecture already precludes this class of bug: RenderPipeline.render is serialized by an internal lock and returns read-back buffers, never live textures. Note for the future: if we port the spot densitometer (flagged 2026-07-13), keep hover readouts on those read-back buffers, not on GPU probes.
  • c728874 more ASCII-encode EXIF crash fixes — their metadata writer.
  • 2a62c6a camera-scanning follow-ups (RGB-only Scanlights, live-view polish, crash logging) — feature we don't ship.
  • 3961b4d UX polish (drag-to-heal, Enter confirms crop, cursor/tooltip tweaks) — heal is out of scope; "Enter confirms crop" is a small UX idea we could copy independently of upstream.
  • a033b92, 80041ca, 0500404 — changelog/lint churn.

To port (proposed, not yet implemented — carried over from 2026-07-13, re-confirmed still open):

  • TIFF export compression (fb4b7a7, upstream default Deflate+predictor): our Exporter.swift still writes uncompressed TIFF. Best-value small item; verify ImageIO Deflate support, else LZW.
  • 77c8113 spot densitometer + density_histogram metric + zone strip — useful darkroom tool we lack; moderate effort (new GPU metric + UI), no parity impact.
  • "Negative character" diagnostic (flat/contrasty vs default_grade_range()) — cheap, blocked on us having a stats read-out surface.
  • Fine rotation + Straighten tool (7f4b7a7) — geometry feature, not pipeline; still open as a feature candidate.

2026-07-13 — through f279337 (0.37.0 release, 25 commits)

Kernel status: untouched. No changes to normalization/curve logic, EXPOSURE_CONSTANTS, or the characterization goldens — no fixture re-dump needed. Only two commits touched features/exposure/ at all:

Ported: nothing (nothing required).

Candidates flagged (not yet decided):

  • 77c8113 Analysis panel: merged H&D chart, spot densitometer, zone strip. New density_histogram metric (120 bins over −0.1…1.1 normalized-log density, analysis.py/density_hist.wgsl) computed per render; the densitometer maps hover → normalized-log coords → zone/density read-out. Presentation-layer, but a genuinely useful darkroom tool we lack.
  • stats.py rework (same PR): "Negative character" diagnostic — measured density range vs default_grade_range(), ratio <0.80 → "flat (≈N−1)",

    1.25 → "contrasty (≈N+1)". Cheap to add if we grow a stats read-out.

  • fb4b7a7 default TIFF compression LZW → Adobe Deflate (ZIP) + horizontal predictor. Our export currently writes uncompressed TIFF (no compression options set in Exporter.swift); worth adding compression, though ImageIO's Deflate-TIFF support needs verifying (LZW is the safe bet).
  • 7f4b7a7 clockwise-positive fine rotation + Straighten reference-line tool — we only have 90° steps; geometry feature, not pipeline.

Not applicable / out of scope:

  • db72e9f CPU/GPU parity for B&W renders (post-curve luma collapse in exposure.wgsl is mode == 1 only; we don't ship B&W). Its histogram sub-fix (bin from float output before quantization, drop the 4× stride) is a CPU-preview artifact fix — our histogram256 already bins the linear float content on GPU.
  • e56c199 preserve edits when EXIF rewrites change the file hash — NegPy keys sidecars by content hash; ours are filename-keyed.
  • 1deeba6 batch export path/mode bug — their session-export plumbing.
  • Toners (4a3cd34), crosstalk profile editor (0bba263), retouch/heal & dust (9b04f49, 05b8763), dodge-burn masks (2cf6afd), camera scanning (c558a16, 15d15c7), shortcut-editor UI (4 commits), EXIF string sanitizing (8363495), changelog/screenshot churn — all stages/features we deliberately don't ship.

2026-07-11 — through cac6396 (v0.35 → v0.36 era, ~20 commits)

Ported:

  • True Black (BPC): t → (t−b)/(1−b), b referenced to physical d_max; negative toe raises the clip point. (SwiftInvert later defaulted it ON — our divergence; NegPy ships it off.)
  • toe_height 0.35 → 0.90 with toe_grade_strength × 0.35/0.90 rescale (perceptual toe/shoulder balance; default output bit-compatible).
  • Cast removal: confidence scaling always on (auto toggle removed).
  • flare/surround deleted (were always-off in SwiftInvert).

Deliberately skipped:

  • Per-layer R/G/B trims (grade/toe/shoulder/width/Snap) — per-channel crossover correction; candidate future feature.
  • Split Grade + Zone Density — upstream's convergent equivalent of our tone controls (theirs: zone centers 1.49/0.34, sharpness 4.0, sequential ordering; ours keep 1.40/0.30 @ 3.5 with documented monotone bounds).
  • Midtone-gamma user slider (cheap to add if wanted).
  • C41 denoise (lab stage — not ported), multi-core CPU kernels (we're GPU), camera-scanning feature work.

Known-unreviewed at time of writing: local NegPy has already pulled past the marker (14 commits, cac6396..c558a16, mostly camera-scanning work by the titles) — NOT yet reviewed for pipeline changes.

2026-07-16 — film-base sampling and the cast experiments REMOVED

The 2026-07-15 "Ported" entry for 77c8113-adjacent film-base sampling is superseded: Sample Film Base was removed after its trial, together with the three patent-derived cast experiments built 2026-07-16 (saturation- weighted colour metering, tempered cast removal, roll balance — see PLAN-cast-experiments.md at 2b73c5d for the mechanisms). All were default-off and parity-clean; all verified mechanically correct end to end.

Why removed: the trial standard was "visibly better on real rolls", and none met it. On neutral-rich frames every method converges with the existing statistical estimate BY DESIGN (film-base agreed within 0.02D; weighted metering moved bounds ~0.01D; tempered cast at shipping constants shifts pixels ~1/7 of an 8-bit step). The existing two-axis bounds + confidence- gated neutral axis already handle these rolls well; the added UI surface wasn't paying for itself. Direction judged wrong by the user 2026-07-16.

Do not re-propose without new evidence — specifically, a real roll where casts visibly fail (dominant color, no neutrals, no usable rebate). If that roll appears, the removed work is complete and recoverable: fed271a (film-base sampling), fa3e095 (weighted metering), 36ae788 (tempered cast), 420f583 (roll balance), 2b73c5d (plan) — local-only commits, never pushed, reachable via reflog until gc.

Kept: the NegPy 0.38 constants port (1c1c3cb, this entry's parent), the spot densitometer / zone strip / negative character (shipped earlier and in regular use), and the research findings in the 2026-07-16 conversation. The densitometer remains the darkroom read-out surface; sidecars and the one roll-profile dotfile were scrubbed of the removed features' keys.