Loupe

Press ⌘2 to view one photograph with zoom, a filmstrip and an optional info panel.

Zoom and pan. Double-click the photograph or press space for 100%, then repeat for fit. Zoom centres on the pointer, or on the photograph’s centre if the pointer is outside it. Pinch to zoom around the detail under your fingers. A two-finger double-tap also toggles 100% and fit. Drag or use a two-finger trackpad drag to pan.

The zoom range is 25% to 400%, with fit below 25%. The slider has evenly spaced stops at 25%, 50%, 100%, 200% and 400%. At 100%, one original pixel occupies one physical display pixel.

Double-click the background beside the photograph, or press esc, to return to fit when zoomed. At fit, this returns to Grid. Moving the pointer over the photograph reveals a back chevron in the top-left corner, which returns to Grid at any zoom.

Available detail. INTERP means the display is enlarging the available rendered pixels. It always appears above 100%; below that it depends on the current render size. Fit never shows it. For example, a render at 55% of original size can show INTERP from about 60% zoom.

Develop can render the visible region at original resolution after zooming or panning stops. INTERP then clears where original detail is available. Slider drags temporarily use a softer render. Small pans reuse the detailed region; larger pans render again. Crop, masks, repairs, focus peaking, find-dust and look previews disable this region rendering.

Info panel. Press I to show it. With one photograph selected, RATING and VERDICT provide stars and Reject, Keep and Unset. Other sections show:

• FRAME: filename, capture and import dates, file kind, dimensions and megapixels.
• DEVELOP: development date and selected treatment, when edited.
• CAPTURE: camera, lens, exposure, aperture and ISO.
• SOURCE: original file location.

Unknown values show not read yet. The panel also works over Grid. Rating and verdict controls hide for multiple selections.

Histogram. The panel measures decoded original pixels across 256 bins. It shows needs the original, then measuring, before the plot. Even a reduced original decode can provide a measurement; proxies cannot. Measurements are cached for the picture, edits and decode quality that produced them. Returning to unchanged pixels reuses their measurement; replacing the picture or changing its crop cannot attach an older result to the new image.

Click a clipping gutter, or press J for highlights and ⇧J for shadows, to show clipped pixels. Click a channel letter or histogram lobe to isolate it; ⌥-click selects two channels. Hover for the level and channel values. A heading control removes channel colours. Develop uses the same histogram, with luminance only in Monochrome.

Press K for green focus-peaking marks once an original decode is available.

Image quality and downloads. Frames starts with a cached thumbnail, then uses the embedded preview or RAW decode when it improves the image. A smaller embedded preview does not replace a larger cached render.

Pausing on a photograph starts the quality upgrade after 700 ms while moving quickly, or 500 ms after three slower steps. An iCloud original is fetched at that point. Moving on before the delay avoids the fetch. A separate preparation pass builds the render Develop will need; the control-band ring shows progress.

The status bar reports rendition source, size, activity and errors with a retry option. Click the rendition readout for a panel listing all four quality levels, the current level, decoder version, histogram source and original-cache status. Load original fetches an unavailable original. For a disconnected volume, reconnect it first; the panel has no download button.

Fetching an original also fills missing EXIF, including camera, lens and ISO. In Loupe, the read starts when decoded pixels arrive and updates the displayed capture details in place. Reopening a cached original retries missing EXIF without downloading it again; simultaneous requests share the pending read. When capture details are empty, the status bar distinguishes “EXIF not read yet,” “Reading EXIF…” in Loupe, and “EXIF unavailable” after a completed read found none. VoiceOver uses the same messages. The Photos source panel can also fill missing capture metadata.

Filmstrip and marks. Drag the filmstrip’s upper edge to resize it. Height is shared with Compare and Develop, and the current photograph stays visible. Shift-click or Command-click additional photographs in the filmstrip to open Compare with those photographs selected. Press F or its button beside the info toggle to hide it. Each mode remembers visibility across launches; Loupe and Compare share that choice within Browse or Choose.

The status bar continues to show verdict, development mark and stars when the strip is hidden. Use the rail or info panel to change them.

See Monochrome, Focus peaking, Grid, Storage.