Layer Basics 3

5. You can quickly select all opaque areas in a layer by Cmd/Ctrl-clicking the layer in the Layers palette. When you hold down the Cmd/Ctrl key, the mouse pointer turns into a hand with a square selection marquee (below left). The result will be that all the pixels in the layer will be selected. You will see a row of "marching ants" around the selected pixels in the layer (below right).

6. To delete a layer, click it and drag it to the Trash button in the Layers palette (below left). The result is shown below right.

Layer Basics 2

2. You can turn layer visibility on and off and completely change the appearance of an image without permanently affecting a single pixel. The eye icon to the left of each layer controls its visibility. A layer is made visible or hidden by clicking its eye icon (below left). The result is the same Photoshop document shown previously with the exception that one of its layers has been hidden revealing the white background underneath.

3. Opt/Alt-clicking a layer's eye icon will make it visible and will hide all others (below left). In the example below, the layer named "paint" becomes the only visible layer (below right). Note that the layer named "photo" is still highlighted. The highlighted layer in the Layers palette indicates that it is the active (or selected) layer. This means that all editing in the document window will be applied to the active layer.

4. Click a layer to activate it (circled below left). Now all editing in the document window will be applied to the "paint" layer.

Note that there is no change in the appearance of the document window (below right). Look to the Layers palette to see which layer is active, not to the document window.

Layer Basics 1

One of Photoshop's most powerful features is the use of layers. Each layer in a Photoshop document is a separate image which can be edited apart from any other layer. A layer can be envisioned as an image on a sheet of clear material. Together, all the layers form a stack of images:

1. Layers are managed with the Layers palette (below left). The Layers palette displays a small thumbnail view of each layer to help identify it. The appearance of a Photoshop document is a view of the layer stack from the top down (below right).