Stacker manual

Touch up

An engine judges sharpness; it does not know what the picture is of. Now and then it picks the wrong frame for a patch: a halo along a bright edge, a soft band where a hair crossed a background, a leg that moved. Touch up fixes those by painting real pixels from one of your images, or from another engine’s result, onto the result you keep.

Touch up is a repair tool, not an editor. Every stroke copies pixels that exist in one of your photographs, in another stack, or (with Heal) in the result’s own surroundings; nothing is invented and nothing is colour-corrected beyond Heal’s level match, Clone’s Match tone and the Defringe brush’s fringe repair. The look still belongs to Finish.

The step opens once a stack has run. Until then the view says Nothing to retouch yet and the step card reads Stack first — touch-up paints source pixels onto the fused result. The panel on the right carries only that reminder; every tool of this step is in the toolbar above the two views.

Base and source

The two views are the whole idea of the step. The left view is the base: the result you paint onto. Its caption reads Result · painting onto followed by the engine whose result it is. The right view is the source: what you paint from. Its caption reads Source · painting from followed by the name of the stack or the file name of the image.

Both views share one zoom and one position. Right-drag, middle-drag, or hold the pan key (Space, see Settings › General › Pointer and wheel) and left-drag on either view, or scroll, and both move together, so the spot under the pointer on the left is always the same spot on the right. A stroke dragged on either view copies source pixels onto the result at that same spot; it makes no difference which view you draw on. Draw on the source when you want to see what you are copying, on the result when you want to see what you are covering.

The image list, wherever you have docked it, changes shape on this step. It has three sections:

Each stack card carries a Use as base button (hover: Make this the result you paint onto). It swaps that stack into the Base image section and the old base down into Stacks. Any strokes you have already painted are replayed onto the new base, so changing your mind about the engine does not cost you the retouching. The status bar confirms with Base is and the stack’s name. Clicking the button does not also make the stack the source; result and source would then be identical and a stroke would appear to do nothing.

With only one stack so far, the Stacks section says Only one stack so far — pick more engines on Stack.

Why. A stack result is usually right almost everywhere, and a second engine is usually right in exactly the places the first one is not. Painting one result onto another lets you keep the better of the two in every patch without choosing one engine for the whole picture.

Picking a source quickly

Two shortcuts save a trip to the list:

• Alt-click a spot on the result. While Alt is held, the status bar names the image the engine used at that pixel (pixel from, the file name and its focus step, then Alt-click to paint from it). The click makes that image the source, and the status reads Painting from the image the engine used here with the image’s number. This is the usual first move on a soft patch: the engine’s choice there was close, and one of its neighbours is the sharp one.
• , and . step the source backwards and forwards through the list: the other stacks first, then the source images in stack order. The shortcut names are Select previous image and Select next image; both can be rebound.

Hold X at any time to see the source in place of the result in the left view; let go and the result is back. The shortcut is called A/B — hold to see the source (hold). Painting is paused while it is held.

Companion stacks

When only one engine has run there is nothing to paint from except the source images. The Stacks section then offers a companion instead: a panel titled Add a companion stack with one pill for each engine that could run next (up to three, in the order of your engine list) and a button, Add companion stack. The complementary engine is picked for you: Sharp Regions when the base is Depth Aware, Depth Aware otherwise. Click a different pill to choose another.

The button’s hint says what happens: Stacks the complementary engine and selects it as the paint source; the disagreement overlay lights up where the two engines differ — paint there. The new stack runs, becomes the source, and the status reads Companion layer ready — painting from the engine’s name, bright overlay = where the engines disagree. Once a companion exists, the same offer sits in the list as a card, Add companion stack, until that engine has run too.

The disagreement overlay itself is shown on the Stack step’s view, where Review › Disagreement overlay turns it on and off. Go back one step to see the bright patches, note where they are, and return to paint them.

Why. Depth Aware is smooth and forgiving across soft transitions; Sharp Regions is crisp on fine detail. The two disagree exactly where one of them has made a mistake, so those bright patches are a map of the places worth your attention. Painting the crisp result onto the smooth one, or the other way round, is the classic retouch workflow, and the companion button does the engine juggling in one click.

The brushes

The leftmost card is the brush kind, shown as Brush: and the current kind’s name. Click it for the menu, or press the number keys:

Details is the default and the one to reach for first. It does not copy pixels as they are; it re-runs the detail transfer under the brush, taking the source’s fine structure at every scale and putting it into the result, so a soft patch becomes sharp without a visible edge where the brush stopped. Use it when the result is blurred where the source is sharp.

Clone is the plain copy, for when you want exactly what the source shows: a leg that moved, a blown highlight the other engine handled better. Because it copies tone as well as detail, its edge can show on a soft background; that is what the hardness setting is for. When the source frame is brighter or darker than the result around the repair, tick Match tone beside Hardness: each dab then brings the source to the brightness, contrast and colour of the ring of result just around it before painting, so the patch keeps the source’s detail and takes the result’s tone, and leaves no halo. Projects with matched strokes need this version of Stacker or later to open.

Darken and Lighten are Clone with a rule. Darken changes a pixel only when the source is darker there, so it removes a bright halo around an edge and leaves everything that is already dark alone. Lighten is the mirror: it lifts a dark fringe or a muddy shadow and leaves the highlights alone. The rule is judged pixel by pixel on brightness, so you can paint freely over an area and only the halo changes.

Heal is the one brush that does not read the source pane. At each stroke it looks around the first dab for the patch of the result whose border matches the dab’s border best, on texture alone, brings that patch to the dab’s own brightness and paints it in with Clone’s falloff. It is for dust, a hair across a background, a pollen grain on a petal: small marks the stack carried through from every frame, which no source can fix because every source has them. Keep the brush just wider than the mark; a large brush on a textured subject pulls in a patch that may not belong. A stroke that drags takes its patch from the first dab, so a hair is one short stroke along its length, not a scrub.

Defringe is the second brush that ignores the source pane. It runs the same chroma fringe removal as Finish’s Studio Soft defringe, but only where you paint and on any engine’s result: the purple or green edge around an out-of-focus highlight takes the colour of what surrounds it while its brightness stays. It paints when you release the button rather than as you drag, and the path is drawn as a pale line until then. Projects with defringe strokes need this version of Stacker or later to open.

Drag on either view to paint. A gold ring shows the brush under the pointer and the other view mirrors it, so you can see the brush’s footprint on both at once. Press Esc while dragging to cancel the stroke being painted.

For a straight stroke, hold Shift and click: the line runs from where the last stroke ended to the click, and the next Shift-click carries on from there. With nothing painted yet, the first Shift-click only marks the start. While Shift is held, the line to come is drawn from the start to the pointer.

To keep a brush off part of the picture, use the Paint on menu beside the brush: its icon shows the choice. All paints anywhere. Subject paints only on the subject, and Background only around it, both read from the same subject matte Finish’s Subject and Background masks use. The brush fades out where the subject’s edge is, so a repair to the background around a leg or an antenna can sweep right up to it without touching it. Every brush follows the setting. Details keeps or skips each pixel whole, since its detail transfer is all or nothing. The matte comes from the stacked result before any touch up, so it stays the same while you paint. Projects with strokes kept to one side need this version of Stacker or later to open.

Tip. Work at 100% or 200% and paint small. A stroke is cheap to undo, and a few short strokes on the exact halo read better than one sweep that also changes the pixels around it.

Size and hardness

Size is the brush radius in full-resolution pixels, from 1 to 400, with a number box beside the slider to type an exact value. The [ and ] keys step the radius down or up by a quarter at a time without leaving the image; the slider’s hint shows the keys you have bound. The default radius is 50 pixels, a brush 100 pixels across.

Hardness feathers the edge of Clone, Darken and Lighten strokes; it is greyed out for Details, which is always hard-edged. The slider runs from 0 to 1, default 0.5. At 1 the brush is a hard disc. Softer settings widen the disc by up to 40 % and feather the blend from the centre out, so the copied pixels fade into the result instead of stopping at a line. A pixel’s blend only ever increases: going back over an area never fades it, and a second pass with a harder setting completes a copy that a soft pass started.

Why. A hard edge is right for Details, which blends by nature. For the cloning brushes a soft edge is what hides the repair: the eye finds a line where tone changes abruptly, not a gradual change over a few dozen pixels.

History

Every stroke is kept, in order, as a step of the edit history Finish shares. Undo (⌘Z) takes the last step back — the last stroke, or a look or layer change made on Finish since; if you are in the middle of a stroke it cancels that stroke instead. Redo (⌘⇧Z) puts it back. Click the strokes card beside them for the History list: every step to jump to, and Toggle last edit, which switches the newest one off and on. Clear (⌘⌫) removes every stroke and leaves the fused result as it was; its hint reads Remove every stroke with your key. Clear is unavailable while a job is running or when there is nothing to clear.

The strokes card beside the history buttons shows where your strokes fall on the result as a small map, the count (1 stroke, 12 strokes) and on followed by the engine whose result they are painted onto. Strokes are saved with the project and replayed when it is opened, and replayed again when you change the base or re-develop the images.

View and focus map

The View card zooms both views together. Fit (⌘0) shows the whole image, 100% (⌘1) shows one image pixel per screen pixel, 200% (⌘2) shows two. The readout beside them shows the current zoom.

Focus map tints what is sharp in either view so your eye knows where to look. Press F to cycle it, or click the tile for its menu:

The menu also carries the tint colour (Red, Yellow, White, Blue) and a Peaking slider: lower lights more of the picture; higher keeps only the sharpest. The map is display only; painting is unaffected. The colour and peaking are shared with the focus peaking on Capture and with Settings, so a change here changes them there too.

Tip. Source only is the quick way to confirm a source before painting from it: if the patch you are about to fix is not tinted on the right, that image is not the sharp one, and , or . will find the one that is.

Export

Export saves the retouched result in the format you pick. Each entry opens that format’s settings, then asks where to save:

This is the same export the Finish step offers, with the retouched result as the picture. Finish adds the stamp and the share set on top; The Finish chapter covers the dialogs.

Status messages on this step

The status bar’s left side lists what the mouse and keys do here, with your own shortcuts filled in: Left-drag paints source onto result · right-drag or hold Space to pan · the two brush-size keys · the undo key · the cancel key cancels a stroke · File › Settings › Shortcuts to rebind.

While the pointer is over the result, the right side names the image the engine used at that pixel: pixel from the file name, its focus step when the camera recorded one, and Alt-click to paint from it. The step card itself shows nothing while the step is available; when it is dark, hovering it reads Stack first — touch-up paints source pixels onto the fused result, or, with fewer than two images, Touch-up paints source images onto a stack — import a focus bracket first.

Messages that appear as you work: