Pick the tool that matches the edge
There is no best selection tool, only a best tool for a given edge:
- Object Selection / Select Subject — a clear subject against a distinct background. Often 90% correct in one click.
- Quick Selection — broad areas of similar tone. Fast, sloppy, fine as a starting point.
- Pen tool — hard man-made edges: cars, buildings, packaging. Slow but exact, and the path is re-editable.
- Colour Range — a subject separated by colour rather than shape, like a sky.
- Channels — hair, fur, smoke, glass. See cutting out hair.
Rough first, refine as a mask
Chasing a perfect selection with marching ants is the slow way to work. Get to roughly 90%, click the mask button, and fix the remaining 10% with a brush on the mask where you can actually see the result against the background.
Select and Mask
The Select and Mask workspace handles the edge cases. The controls that matter:
- Refine Edge Brush — for hair and fur. Paint over the transition zone and let Photoshop work out the boundary.
- Shift Edge — pull the selection inward slightly (−10% or so) to drop the background fringe that otherwise haloes a cutout.
- Decontaminate Colors — removes the old background's colour cast from semi-transparent edge pixels. Essential when the backgrounds differ sharply in colour.
- Output to: New Layer with Layer Mask — always. Never output to a plain layer; you lose the ability to fix it.
Feather the right amount
A selection with zero feather looks pasted on, because real lenses do not produce infinitely sharp edges. One or two pixels is usually right for a sharp subject at full resolution, and more if the subject is slightly out of focus. Match the feather to the actual softness of the edge in the photo.
Save the selection
Select → Save Selection stores it as an alpha channel in the file. If a selection took more than a minute to build, save it — you will want it again for a separate colour or sharpening pass.