Add selectable EXIF ImageDescription fields for process and scanning metadata

docs/USER_GUIDE.md

@@ -519,7 +519,7 @@ Archival metadata for the **original analog capture** (camera, lens, film, proce
 
 **Exposure**: optional original shutter/aperture/ISO. Click the lock to edit a free-text string (e.g. `1/125s f/2.8 ISO 400`).
 
-**Metadata preview**: a live view of exactly what will be embedded, grouped by capture / scan / process / file.
+**Metadata preview**: a live view of exactly what will be embedded, grouped by capture / scan / process / file. **Description…** opens a checklist of which fields join into EXIF `ImageDescription`. Defaults are camera, lens, film stock, and ISO — format, developer, push/pull, and scanning are off until you enable them. Confirming **Description…** sets that frame's selection and becomes the sticky default for other frames that don't have their own; the last confirm on the roll wins. Sync metadata / Sync settings can also copy a frame's selection with the rest of the metadata.
 
 When you set capture gear, it's written to standard EXIF and the digitizing rig is preserved separately in `negpy:Scan*` XMP tags. Leave gear unset and your scanner/DSLR stays visible in EXIF instead.
 

negpy/desktop/session.py

@@ -557,6 +557,20 @@ def _apply_sticky_settings(self, config: WorkspaceConfig, only_global: bool = Fa
                 metadata=replace(config.metadata, protect_original_metadata=bool(sticky_protect)),
             )
 
+        # Description fields: unset (None) inherits the sticky roll choice; an explicit
+        # per-frame tuple from Description… is left alone.
+        if config.metadata.description_fields is None:
+            from negpy.features.metadata.models import resolve_description_fields
+
+            sticky_desc = self.repo.get_global_setting("last_description_fields")
+            config = replace(
+                config,
+                metadata=replace(
+                    config.metadata,
+                    description_fields=resolve_description_fields(None, sticky_desc),
+                ),
+            )
+
         # Flat-field profile and distortion k1 are rig-global: the active profile's
         # values always override the per-file ones. New files default to enabled when a
         # profile is active; saved files keep their toggle.

negpy/desktop/settings_catalog.py

@@ -193,6 +193,12 @@ def _row(label, section, *fields, channels="", fmt=None) -> SettingRow:
         _row("Scanning", "metadata", "scanning"),
         _row("Exposure Override", "metadata", "exposure_override"),
         _row("Protect Original Metadata", "metadata", "protect_original_metadata"),
+        _row(
+            "Description Fields",
+            "metadata",
+            "description_fields",
+            fmt=lambda v: (", ".join(str(x) for x in v[0]) if v[0] else "—"),
+        ),
     )),
     ("Export", (
         _row("Format", "export", "export_fmt"),

negpy/desktop/view/sidebar/metadata.py

@@ -17,10 +17,12 @@
 from negpy.desktop.view.styles.templates import field_label, hint_label
 from negpy.desktop.view.styles.theme import THEME
 from negpy.desktop.view.widgets.collapsible import CollapsibleSection
+from negpy.desktop.view.widgets.description_fields_dialog import DescriptionFieldsDialog
 from negpy.desktop.view.widgets.gear_library_dialog import GearLibraryDialog
 from negpy.desktop.view.widgets.searchable_gear_combo import SearchableGearCombo
 from negpy.features.metadata.gear_logic import metadata_from_gear
 from negpy.features.metadata.gear_models import GearLibrary
+from negpy.features.metadata.models import DEFAULT_DESCRIPTION_FIELDS
 from negpy.features.metadata.payload import build_metadata_payload
 from negpy.services.assets.gear import GearProfiles
 
@@ -50,6 +52,7 @@ def _init_ui(self) -> None:
 
         self._dirty = False
         self._exif_locked = {"exposure": True}
+        self._description_fields: tuple[str, ...] = conf.description_fields or DEFAULT_DESCRIPTION_FIELDS
 
         self.protect_check = QCheckBox("Protect original metadata")
         self.protect_check.setChecked(conf.protect_original_metadata)
@@ -161,8 +164,15 @@ def _init_ui(self) -> None:
         preview_layout.setContentsMargins(0, 0, 0, 0)
         preview_layout.setSpacing(4)
 
+        preview_top = QHBoxLayout()
+        preview_top.setContentsMargins(0, 0, 0, 0)
+        preview_top.setSpacing(THEME.space_sm)
         preview_hint = hint_label("Written to exported files on export.")
-        preview_layout.addWidget(preview_hint)
+        preview_top.addWidget(preview_hint, 1)
+        self.description_fields_btn = QPushButton("Description…")
+        self.description_fields_btn.setToolTip("Choose which fields join into EXIF ImageDescription.")
+        preview_top.addWidget(self.description_fields_btn)
+        preview_layout.addLayout(preview_top)
 
         self.preview_rows = QVBoxLayout()
         self.preview_rows.setSpacing(2)
@@ -216,6 +226,7 @@ def _make_exif_field(self, key: str, layout: QVBoxLayout) -> QLineEdit:
 
     def _set_metadata_controls_enabled(self, enabled: bool) -> None:
         self._metadata_controls.setEnabled(enabled)
+        self.description_fields_btn.setEnabled(enabled)
 
     def _apply_lock_style(self, edit: QLineEdit, locked: bool) -> None:
         if locked:
@@ -243,6 +254,7 @@ def _toggle_exif_lock(self, key: str, edit: QLineEdit, btn: QToolButton, checked
 
     def _connect_signals(self) -> None:
         self.protect_check.toggled.connect(self._on_protect_toggled)
+        self.description_fields_btn.clicked.connect(self._open_description_fields)
         self.preset_combo.selection_changed.connect(self._on_preset_changed)
         self.preset_clear_btn.clicked.connect(self._on_preset_clear)
         self.camera_combo.selection_changed.connect(self._on_gear_changed)
@@ -271,6 +283,26 @@ def _on_protect_toggled(self, checked: bool) -> None:
         )
         self._schedule_preview()
 
+    def _open_description_fields(self) -> None:
+        dlg = DescriptionFieldsDialog(self._description_fields, self)
+        if dlg.exec() != dlg.DialogCode.Accepted:
+            return
+        self._description_fields = dlg.selected_fields()
+        self.update_config_section(
+            "metadata",
+            persist=True,
+            render=False,
+            readback_metrics=False,
+            description_fields=self._description_fields,
+        )
+        # Sticky is only updated here — not on every metadata save — so the last
+        # Description… confirm wins for unset frames on the roll.
+        self.controller.session.repo.save_global_setting(
+            "last_description_fields",
+            list(self._description_fields),
+        )
+        self._schedule_preview()
+
     def _refresh_gear_combos(self, *, force: bool = False) -> None:
         conf = self.state.config.metadata
         self._gear_library = GearProfiles.load_library()
@@ -456,6 +488,7 @@ def sync_ui(self) -> None:
             self.push_pull_combo.setCurrentIndex(idx)
             self.scanning_edit.setText(conf.scanning)
             self.sync_check.setChecked(conf.sync_to_batch)
+            self._description_fields = conf.description_fields or DEFAULT_DESCRIPTION_FIELDS
 
             if conf.exposure_override:
                 self._set_exif_text_quiet("exposure", conf.exposure_override)
@@ -498,6 +531,33 @@ def _update_exif_display(self) -> None:
         else:
             self._set_exif_text_quiet("exposure", "")
 
+    def _preview_metadata_config(self):
+        """MetadataConfig from the live form so preview tracks edits before debounce persist."""
+        conf = self.state.config.metadata
+        fmt = self.format_combo.currentText()
+        pp_idx = self.push_pull_combo.currentIndex()
+        exposure_override = ""
+        if not self._exif_locked.get("exposure", True):
+            exposure_override = self.exposure_edit.text().strip()
+        else:
+            exposure_override = conf.exposure_override
+
+        return replace(
+            conf,
+            gear_preset_id=self.preset_combo.selected_id(),
+            camera_id=self.camera_combo.selected_id(),
+            lens_id=self.lens_combo.selected_id(),
+            film_stock_id=self.film_stock_combo.selected_id(),
+            format=fmt,
+            format_other=self.format_other_edit.text().strip() if fmt == "Other" else "",
+            developer=self.developer_edit.text().strip(),
+            push_pull=PUSH_PULL_VALUES[pp_idx] if 0 <= pp_idx < len(PUSH_PULL_VALUES) else 0,
+            scanning=self.scanning_edit.text().strip(),
+            sync_to_batch=self.sync_check.isChecked(),
+            exposure_override=exposure_override,
+            description_fields=self._description_fields,
+        )
+
     def _update_preview(self) -> None:
         while self.preview_rows.count():
             item = self.preview_rows.takeAt(0)
@@ -516,7 +576,7 @@ def _update_preview(self) -> None:
         if current_hash and current_hash in self.state.source_exif:
             source_exif = self.state.source_exif[current_hash]
 
-        payload = build_metadata_payload(conf, self._gear_library, source_exif)
+        payload = build_metadata_payload(self._preview_metadata_config(), self._gear_library, source_exif)
         sections = payload.to_preview_sections()
 
         self.preview_empty.setText("Select gear or enter process metadata to see a preview.")

negpy/desktop/view/widgets/description_fields_dialog.py

@@ -0,0 +1,41 @@
+from PyQt6.QtWidgets import QCheckBox, QDialog, QDialogButtonBox, QVBoxLayout
+
+from negpy.desktop.view.styles.templates import hint_label
+from negpy.features.metadata.models import (
+    DESCRIPTION_FIELD_LABELS,
+    DESCRIPTION_FIELD_ORDER,
+    normalize_description_fields,
+)
+
+
+class DescriptionFieldsDialog(QDialog):
+    """Pick which metadata values join into EXIF ImageDescription."""
+
+    def __init__(self, selected: object, parent=None):
+        super().__init__(parent)
+        self.setWindowTitle("Description fields")
+        self.setMinimumWidth(320)
+
+        root = QVBoxLayout(self)
+        root.addWidget(
+            hint_label(
+                "Checked fields are joined with • into the export ImageDescription. "
+                "Empty values are skipped."
+            )
+        )
+
+        enabled = set(normalize_description_fields(selected))
+        self._checks: dict[str, QCheckBox] = {}
+        for key in DESCRIPTION_FIELD_ORDER:
+            box = QCheckBox(DESCRIPTION_FIELD_LABELS[key])
+            box.setChecked(key in enabled)
+            self._checks[key] = box
+            root.addWidget(box)
+
+        buttons = QDialogButtonBox(QDialogButtonBox.StandardButton.Ok | QDialogButtonBox.StandardButton.Cancel)
+        buttons.accepted.connect(self.accept)
+        buttons.rejected.connect(self.reject)
+        root.addWidget(buttons)
+
+    def selected_fields(self) -> tuple[str, ...]:
+        return normalize_description_fields(key for key, box in self._checks.items() if box.isChecked())

negpy/features/metadata/models.py

@@ -12,6 +12,54 @@
     3: "Push +3",
 }
 
+# Ordered keys for EXIF ImageDescription; only non-empty values are joined.
+DESCRIPTION_FIELD_ORDER: tuple[str, ...] = (
+    "camera",
+    "lens",
+    "film",
+    "iso",
+    "format",
+    "developer",
+    "push_pull",
+    "scanning",
+)
+DESCRIPTION_FIELD_LABELS: dict[str, str] = {
+    "camera": "Camera",
+    "lens": "Lens",
+    "film": "Film stock",
+    "iso": "Film ISO",
+    "format": "Format",
+    "developer": "Developer",
+    "push_pull": "Push / Pull",
+    "scanning": "Scanning",
+}
+# Preserve pre-selector behaviour: gear only.
+DEFAULT_DESCRIPTION_FIELDS: tuple[str, ...] = ("camera", "lens", "film", "iso")
+_DESCRIPTION_FIELD_SET = frozenset(DESCRIPTION_FIELD_ORDER)
+
+
+def normalize_description_fields(fields: object) -> tuple[str, ...]:
+    """Keep known keys in canonical order (JSON lists round-trip cleanly)."""
+    if fields is None:
+        return DEFAULT_DESCRIPTION_FIELDS
+    if isinstance(fields, str):
+        raw = {fields}
+    else:
+        try:
+            raw = set(fields)
+        except TypeError:
+            return DEFAULT_DESCRIPTION_FIELDS
+    return tuple(k for k in DESCRIPTION_FIELD_ORDER if k in raw and k in _DESCRIPTION_FIELD_SET)
+
+
+def resolve_description_fields(fields: object, sticky: object = None) -> tuple[str, ...]:
+    """Per-frame fields if set; otherwise sticky (or gear-only defaults)."""
+    if fields is not None:
+        return normalize_description_fields(fields)
+    if sticky is not None:
+        return normalize_description_fields(sticky)
+    return DEFAULT_DESCRIPTION_FIELDS
+
 
 @dataclass(frozen=True)
 class MetadataConfig:
@@ -49,3 +97,14 @@ class MetadataConfig:
     protect_original_metadata: bool = False
 
     exposure_override: str = ""  # free-text e.g. "1/125s f/2.8 ISO 400"; empty = use source EXIF
+
+    # EXIF ImageDescription field set. None = inherit sticky roll choice on open;
+    # an explicit tuple (from Description…) is per-frame and not overwritten by sticky.
+    description_fields: Optional[tuple[str, ...]] = None
+
+    def __post_init__(self) -> None:
+        if self.description_fields is None:
+            return
+        normalized = normalize_description_fields(self.description_fields)
+        if normalized != self.description_fields:
+            object.__setattr__(self, "description_fields", normalized)

negpy/features/metadata/payload.py

@@ -8,7 +8,7 @@
 
 from negpy.features.metadata.exif_read import ScanExif, extract_scan_from_exif
 from negpy.features.metadata.gear_models import GearLibrary
-from negpy.features.metadata.models import MetadataConfig, PUSH_PULL_LABELS
+from negpy.features.metadata.models import MetadataConfig, PUSH_PULL_LABELS, normalize_description_fields, DEFAULT_DESCRIPTION_FIELDS, resolve_description_fields
 
 _NEGPY_SOFTWARE = "NegPy"
 NEGPY_SOFTWARE = _NEGPY_SOFTWARE
@@ -197,22 +197,35 @@ def _apex_from_f_number(f_number: float) -> float:
     return 2.0 * math.log(f_number, 2.0)
 
 
-def build_image_description(payload: MetadataPayload) -> str:
-    """Human-readable summary: camera • lens • film • ISO."""
+def build_image_description(payload: MetadataPayload, fields: object = None) -> str:
+    """Human-readable EXIF ImageDescription from the selected field set."""
+    enabled = frozenset(normalize_description_fields(fields if fields is not None else DEFAULT_DESCRIPTION_FIELDS))
     parts: list[str] = []
-    camera = payload.camera_display()
-    if camera:
-        parts.append(camera)
-    lens = payload.lens_display()
-    if lens:
-        parts.append(lens)
-    if payload.film_stock:
+    if "camera" in enabled:
+        camera = payload.camera_display()
+        if camera:
+            parts.append(camera)
+    if "lens" in enabled:
+        lens = payload.lens_display()
+        if lens:
+            parts.append(lens)
+    if "film" in enabled and payload.film_stock:
         parts.append(payload.film_stock)
-    if payload.iso is not None:
+    if "iso" in enabled and payload.iso is not None:
         parts.append(f"ISO {payload.iso}")
+    if "format" in enabled and payload.film_format:
+        parts.append(payload.film_format)
+    if "developer" in enabled and payload.developer:
+        parts.append(payload.developer)
+    if "push_pull" in enabled and payload.push_pull and payload.push_pull != "Normal":
+        parts.append(payload.push_pull)
+    if "scanning" in enabled and payload.scan_method:
+        parts.append(payload.scan_method)
     if parts:
         return " • ".join(parts)
-    return payload.film_stock or ""
+    if "film" in enabled:
+        return payload.film_stock or ""
+    return ""
 
 
 def build_metadata_payload(
@@ -296,8 +309,9 @@ def build_metadata_payload(
         push_pull=push_pull,
     )
 
-    desc = build_image_description(draft)
-    if not desc and config.film:
+    desc_fields = resolve_description_fields(config.description_fields)
+    desc = build_image_description(draft, desc_fields)
+    if not desc and config.film and "film" in desc_fields:
         desc = config.film.strip()
 
     exif_flags = compute_exif_write_flags(config, draft)