ACE Selections and Compositing 3 — Questions and Answers
Question 1: What does increasing the 'Feather' value in the Options bar before drawing a Marquee selection do?
- Expands the selection boundary outward
- Creates a soft-edged transition at the selection border (Correct answer)
- Anti-aliases the selection edge
- Snaps the selection to the nearest content edge
Correct answer: Creates a soft-edged transition at the selection border
Feathering creates a gradual fade at the selection border, so any edits or deletions blend softly rather than creating a hard cutout.
Question 2: Which tool option allows the Quick Selection tool to automatically subtract from an existing selection as you drag?
- Holding Shift while dragging
- Holding Alt/Option while dragging (Correct answer)
- Enabling 'Auto-Enhance' in the Options bar
- Switching to the 'Subtract from Selection' icon in the Options bar
Correct answer: Holding Alt/Option while dragging
Alt/Option+drag switches the Quick Selection tool to subtraction mode on the fly, removing the painted areas from the current selection.
Question 3: A luminosity mask targets pixels for selection based on their brightness values. Where in Photoshop can you create a luminosity mask most directly?
- By Ctrl/Cmd+clicking the composite RGB channel in the Channels panel (Correct answer)
- Via Select > Color Range > Highlights
- Through the Gradient Map adjustment layer dialog
- By painting on a new alpha channel with the Brush tool
Correct answer: By Ctrl/Cmd+clicking the composite RGB channel in the Channels panel
Ctrl/Cmd+clicking the RGB composite thumbnail in the Channels panel loads a selection weighted toward the brightest pixels, which is the definition of a basic luminosity mask.
Question 4: In Select and Mask, what does the 'Smart Radius' checkbox do?
- Automatically adjusts edge detection radius based on the complexity of the edge (Correct answer)
- Increases the selection radius proportionally to canvas zoom level
- Limits edge detection to areas you paint with the Refine Edge Brush
- Applies a fixed 5-pixel radius to the entire selection border
Correct answer: Automatically adjusts edge detection radius based on the complexity of the edge
Smart Radius lets Photoshop vary the detection radius dynamically — wider near complex edges like hair, narrower near clean geometric edges.
Question 5: What happens when you apply Select > Modify > Contract to a selection?
- The selection shrinks inward by the specified pixel amount (Correct answer)
- The selection edge is smoothed to remove jagged pixels
- The selection expands outward by the specified pixel amount
- The feathering radius is reduced
Correct answer: The selection shrinks inward by the specified pixel amount
Contract shrinks a selection uniformly inward, useful for pulling a selection away from the edges of a subject before deleting or masking.
Question 6: Which compositing technique uses the luminosity of one layer to control the visibility of layers beneath it in a group?
- Clipping mask
- Blend If sliders in Layer Style
- Knockout blending option (Correct answer)
- Luminosity blending mode
Correct answer: Knockout blending option
The Knockout option punches through layers within a group, using the top layer's content to reveal layers below or the background based on whether Shallow or Deep knockout is set.
Question 7: When painting a layer mask with a soft brush, which foreground/background color combination will reveal the layer content in the painted area?
- Black foreground
- White foreground (Correct answer)
- 50% gray foreground
- Any color — mask painting ignores hue
Correct answer: White foreground
On a layer mask, white reveals (makes pixels visible) and black conceals — painting with white exposes the layer's content in that area.
ACE Selections and Compositing 3
What does increasing the 'Feather' value in the Options bar before drawing a Marquee selection do?