So, what do you do when you have a picture you love with a background you hate? Why change it, of course! Take, for example, this picture of my cousin David; he loves the pic but hates the pink! So being the wonderful cousin I am I’m going to show him, and you, how to fix that.
Duplicate the image using Ctrl (PC) or Cmd (Mac) plus “J”. The first thing we need to do is select the part of the image we want to change. On this particular image that’s fairly simple. Other backgrounds may be more difficult. There are many tutorials out there, and on TipSquirrel.com, that can show you different ways to do this. For this background we’re just going to use the Quick Selection Tool (Photoshop CS5). On your duplicated layer just “paint” in the background to select it. No holding any buttons down or anything (unless you want to paint a part of the selection out, of course, then you hold the Alt or Opt key down…). Easy breezy!
Next we need to mask the area. When the area you want is selected, go to the bottom of the layers panel and chose the Add Vector Mask icon, the gray rectangle with the white circle inside. By default the mask will be white in the selected area and black in the unselected area. You want this to be the reverse; to invert, simple use keyboard shortcut Cmd or Ctrl plus “I” (for Invert). Make sure you have the mask itself selected when you invert.
Now go back to the original layer. For this next bit you can either use this layer or duplicate it again. I prefer to duplicate it because the next process will change it and I want the original to compare the result. That’s just me. If you’re like me, use keyboard shortcut Ctrl or Cmd “J”, now.
With the layer (orig. or duplicate) selected, go to the bottom of the layers panel and select the Add a New Fill or Adjustment Layer icon (the half white, half black circle), then choose a Hue / Saturation adjustment. In the Hue / Saturation dialog, move the Hue slider around to find the color you want to replace the original. Don’t worry too much about the brightness of the color; concentrate more on a color that looks good with the image.
To calm the brightness down, you can move the Saturation slider a bit to the left. You can also adjust the lightness or darkness of the background with the Lightness slider, if you wish.
Now we need to go back to the original mask and clean things up a bit. Select the brush tool and make sure the foreground color is set to white. The first thing we’ll do is take care of the areas that are now green (or whatever color you changed the background to) and shouldn’t be, the necklace that didn’t get masked out in the first place, for instance. Adjust the brush size to fit the area as you go along using the open and close bracket keys. Zoom in close and go around all the edges of the selected area to make sure that the new color isn’t creeping in where it doesn’t belong.
The next step is to invert the foreground color to black and paint in all the areas where the original background color, in this case that lovely pink, is all painted out.
Now for a word about fringe; you need to pay particular attention to the area around the selection that isn’t super obvious but critical, just the same, to the result of your background change. Nothing screams “Fake!” as much as badly done edges! Be particularly careful around light edges, in this case the skin. If you get sloppy you’ll get green where you don’t want it. In the dark areas, like the hat or t-shirt, you can be a bit less stringent. In fact, I want you to go over the edge into the shirt a bit! There’s a color cast from the pink background reflecting on the shirt, so when you see that, go over it with the brush.
To fix that bit of untidiness we just made, we’re going to soften the mask a bit. With the mask selected, go to Filter > Blur > Gaussian Blur. Move the slider up or down enough to soften the edges without blowing out the areas of the mask around the lighter (skin) areas.
The area where we painted green in the shirt is still very obvious. To make it less so, bring up your color picker by double clicking on the foreground color and choose something around 25% gray.
Paint in those obvious green areas in the shirt with the gray. Soften the edges, if you like, by selecting the blur tool from the tool panel and painting over the area.
Take some time to zoom in and catch all those areas where the wrong color has bled or fringed and you’ll have a background color change no one will ever realize was different at all!