Layers are an essential part of the Photoshop workflow, and this chapter aims to make Layers one of your favorite techniques.
But what are Layers exactly? If you imagine the individual correction steps you perform on an image as a stack of perfectly aligned images where you can only see the top one, you are getting close. But Photoshop Layers can do much more than just document individual correction steps. The three most important characteristics of Layers are:
They have a specific Opacity, with values between 0% (fully transparent) and 100% (fully opaque).
They can be merged with other layers using various ...