post processing - How to do selective-color in Photoshop?

How to make the single color in a photography to be color and other parts changed to B&W?.

Don't know exactly the name of the effect, to be more clear in the following photo I want the green part to be green and other parts( leg and sandal) in B&W..

How to achieve that effect in Photoshop?

Answer

While the posts pointed to by @SteveKemp are good, there is a more general way to accomplish this in Photoshop. Basically, you do this:

• Duplicate the background layer



• Use your masking technique of choice to isolate the area that is to be turned black & white. In the case of the image below, Select > Color Range works nicely to select the blue jeans. After selecting the pants, I can go into QuickMask mode to tidy up the feet by painting on the mask. Many other selection options would work equally well.


• With the selection active, do Image > Adjust > Desaturate and only the stuff selected will be desaturated.

This effect is in a commercial post-production person's must-have bag o' tricks. It's useful in a number of situations and even if it's not to your taste or overused, it's really handy to understand how to do it. Beyond that, it's a short step from understanding how to do selective desaturation to gently dialing back saturation in image areas that are less important to draw attention. This may be a more artful technique.