In Photoshop CS6, the new version of Photoshop, you can use special cropping tool and you are done, but that doesn't mean you cannot achieve the same result with older versions.
There are many different techniques and ways of creating a selective color images in Photoshop, let me show you the one where we use the black & white adjustment layer.
An awesome tutorial suitable for Photoshop beginners and intermediates where we create a cool looking gas planet from scratch, by applying a couple of rendering functions and a few tricks.
Due to work flow optimization guys at Adobe decided to hide some of the filters in Photoshop CS6, if you are missing some of them, you can easily make the visible again.