How can I cut a figure out so I can paint just its background?
Iona Campbell, Scotland
Answer John replies
There are many ways to do this in Photoshop, with several tools at your disposal. It will depend on background complexity, and also the contrast between your character’s silhouette and the background pixels. The quickest way is, of course, the Quick Selection tool, which is just a brush that you use to paint your selection. It automatically detects edge pixels, and you can hold Option/Alt while painting to subtract from the selection if it picks too much.
The Magnetic Lasso tool is an option I prefer, because you can finely adjust its tolerance and frequency. Once you have your character selected, save that selection as a new channel just in case you need it later. Next, using that selection, copy your character to a new layer, then hide that layer. Now you can paint freely over your background with a nice broad brush, with your character preserved on its own layer.
Remember that the lighting on your character will change with the ambient lighting in the scene, so make sure to retouch the character afterwards. Reflective surfaces like polished metal and shiny armour will be especially noticeable if the lighting doesn’t match. An easy way to get a jump on this is to add a Color Balance adjustment layer to your character and tweak the light to be warmer or cooler as the reworked scene demands.
The character, with the new background painted in the back. I’ve added an Adjustment layer to the character, shifting him to a slightly cooler hue.
The original image with a very warm background. The Magnetic Lasso Tool wraps nicely around edge pixels much faster than the regular lasso.