What about Transparency?
One of Photoshop's greatest powers lies in its ability to preserve complex transparency. It is possible to have several different of levels of transparency within a Photoshop document, which leads to greater flexibility in compositing multiple layers together. In order to facilitate a smoother workflow, many people isolate individual pieces of a composition to their own layer. It is possible to place only what you want on an isolated layer. The empty space, often represented by a checkerboard pattern inside of Photoshop, is called transparency. An advantage to isolating elements to their own layers is that the user can quickly load them as a selection and make further changes. Modifying tools can be accomplished by accessing the Options bar. Select the tool required for use, then press to access the Feather or Tolerance field. Type in the number wanted, and then press again to apply it. If there are multiple fields, the user can tab between them.