Let’s open an image and see what to do.
What we want to od is to isolate this lady and put it on a different background, maybe for a magazine, poster or whatever purpose. When we cannot use the traditional selection tools, we need to take a look at the Channels. What we look for is the channel that have the most contrast. In 99% of the cases that channel will be the Blue, but you may never know so make sure you scroll through each of them and pick the right one. Now that we found our channel, we duplicate it.
Press Ctrl + L to bring up the Levels and punch up the blacks.
Pick a brush and fill the rest of our subject with black. For this you can use any tool you like, only the end result matters.
Pick the Magic Wand tool and click on the whites (have a tolerance around 55) then turn off our duplicate channel by clicking on the RGB and go to our Layers panel.
Add a small feather to our selection (Select - Modify - Feather)
At this point you can press Delete to get rid of the original background, but what I like to do is to mask it with a Layer Mask just in case I change my mind later.
Add a new background below our original layer and that’s it. Notice how you can see the new background between the hair.
