Working with Multiple Layers

Video Training

Layer Organization

As Photoshop has continued to evolve, so has its ability to offer powerful layer management. When creating complex designs, such as Web site mock-ups or print advertisements, it is important to maintain control over your design. This includes naming all of your layers, as well as creating relationships or linking between them. Depending on which version of Photoshop you are using, you may find slight differences in layer behavior.

To get some practice, open Ch08_Layer_ Organization.psd from the book's DVD. This file contains several color-coded layers that we will manipulate (the color coding identifies layers that will interact with each other). In the future, you might want to change the color of layers in your own documents to better organize them. To change the label color of a layer, just press Option+double-click (Alt+double-click) on a layer (except for its name).

Selecting Multiple Layers

One of the first skills to learn is how to select multiple layers. Select both the Right Foot and Left Foot layers (which are color-coded red) in the Ch08_Layer _Organization.psd using one of the following methods:

Photoshop CS2 or later: You can click multiple layers to select them. Hold down the Shift key and click to select multiple contiguous layers or use the Cmd (Ctrl) key to select noncontiguous layers.
Photoshop CS or earlier: You will need to highlight the first layer, then click in the link column (adjacent to the visibility column) for the other layers you want to select. Technically, you can only select one layer at a time, but through linking, other layers can be adjusted along with your main selection.

Linking Layers

Linking layers creates a family relationship. When one of the family members moves, the others move along with it (same goes for scale and rotation). You would choose to link two layers together in order to create a relationship of particular elements needing to react to one another. For example, if you had a logo and text that you wanted to scale together (at the same time), you'd link them together. Go ahead and link the Right Foot to its companion Left Foot using one of the following methods:

Photoshop CS2 or later: You can click multiple layers to select them using the techniques mentioned in the preceding section. When all layers that belong together are active, click the link button (chain icon) at the bottom of the Layers palette.
Photoshop CS or earlier: You will need to select the first layer, then click in the link column next to other layers you want to select.

Aligning Layers

A design can look sloppy if the designer relies solely on his or her eyes for a precise layout. Alignment is the process of causing multiple objects to rest on a straight line. This line is usually determined by one of the edges of the selected objects. This is useful to create a professional-looking design where the objects appear precise and organized. Let's align the two layers we are working with:

1.	Select both the Right Foot and Left Foot layers.
2.	Pick the Move tool by pressing V or clicking in the upper-right corner of the Toolbox.
3.	In the Options bar you will notice alignment options. Hover your pointer over each to familiarize yourself with their names.
4.	Select the object that you want to use as a reference point for the alignment. In this case let's use Left Foot.
5.	Click the Align bottom edges button. You'll notice the feet shapes are aligned along their bottom edge.

Distributing Layers

Distribution places an identical amount of space between multiple objects. This can be an important step in creating a professional-looking design. Distribution is similar to Alignment in how it is accessed. However, the intent is slightly different. You will need three or more objects in order to distribute them. Let's distribute a few layers:

1.	Turn off the visibility icons for all layers except Background, Spring, Summer, Fall, and Winter. Click the eye icon to make a layer invisible.
2.	Select Spring, Summer, Fall, and Winter layers.
3.	Choose the Move tool by pressing V or clicking in the upper-right corner of the Toolbox.
4.	In the Options bar you will notice distribution options (to the right of the alignment options). Roll over each to familiarize yourself with their names.
5.	Click the Distribute horizontal centers button to spread the images apart evenly.
6.	Click the Align bottom edges button. Your image will now be evenly aligned and distributed.

Grouping Layers (Layer Sets)

Sometimes you will want to take several layers and treat them as if they were one layer. This is useful for aligning a design composed of multiple images or just general cleanup for organizational purposes. The process of nondestructively joining layers is called grouping. A permanent technique is called merging (see "Merging Layers" later in this chapter), but that is pretty decisive. Instead, let's group these layers together so they still retain their individual identity, yet behave as a group:

Photoshop CS2 or later:

Select Spring, Summer, Fall, and Winter layers using the Cmd-click (Ctrl-click) technique.

Press Cmd+G (Ctrl+G) or choose Layer > Group to place these layers into a new group (which looks like a folder). If you'd like to name the group, double-click the folder's name in the Layers palette.

You can now move these elements together. For example, select both the Background and Group 1, then use the horizontal center and vertical center alignment commands to center these icons on the page.

Photoshop CS or earlier: Select the first layer, then click in the link column next to other layers you want to select.

1.	Select Spring, Summer, Fall, and Winter layers using the link technique. Make sure no other layers are linked to these four.
2.	From the Layers palette submenu (triangle in upper-right corner) choose New Set From Linked.
3.	You can now move these elements together. For example, select the Background and link it to Group 1, then use the horizontal center and vertical center alignment commands to center these icons on the page

Locking Layers

Sometimes you need to protect yourself from your own worst enemy (you). Photoshop gives you the option to lock properties of a layer to prevent accidental modification. Just click the icons next to the word Lock in the Layers palette. You can lock three separate properties (or a combination of the three):

Lock transparent pixels: The grid icon locks all transparent areas of an image, but you can still modify any data that was on the layer prior to locking.
Lock image pixels: The paintbrush icon locks all image pixels in the layer.
Lock position: The arrow icon prevents accidentally moving a layer out of alignment or changing its position.
Lock all: The padlock icon locks all three properties in one click.

Let's try locking a layer:

1.	Turn off the visibility icons for all layers except Background and Key.

2.	Select the Key layer.
3.	In the upper-left corner of the Layers palette, click the Lock transparent pixels and Lock position icons.
4.	Press B to select the Brush tool.
5.	Double-click the foreground swatch and load a color of your choice.
6.	Paint on the Key layer. Notice that the paint stays "inside the lines."
7.	Choose the Move tool (V) and try to move the layer. (A dialog box should pop up telling you no.)

Clipping Mask (Group with Previous)

Sometimes you'll want to place the contents of one layer inside those of another. Designers often use this technique to fill text with a pattern or to constrain a photo to fit inside a shape. The concept is called a Clipping Mask (older versions call it Group with Previous) and it's fairly easy and flexible. All you need to do is place the content layer above the container layer (the one you want to "fill") and choose Layer > Create Clipping Mask.

1.	Turn off the visibility icons for all layers except Background, Ribbon, and Texture.
2.	Select the Texture layer.
3.	Choose Layer > Create Clipping Mask or press Cmd+Option+G (Ctrl+Alt+G). In the Layers palette, you'll see that the layer indents and fills the opaque areas in the Ribbon layer below. Notice that the layer style applied to the layer is still visible.

4.	Choose Layer > Release Clipping Mask or press Cmd+Option+G (Ctrl+Alt+G) to toggle the mask on and off.

Merging Layers

Sometimes, you'll want to permanently merge layers together to commit a design. This can be useful to reduce file size, or to improve compatibility when importing a layered Photoshop document (PSD) file into another application (such as Apple Final Cut Pro or Adobe After Effects). This process is destructive (in that it is permanently joins the layers, which limits future changes). To merge layers, use one of the following methods:

Photoshop CS2 or later: Select two or more layers by Cmd-clicking (Ctrl-clicking) on their names in the Layers palette. For practice, select the Texture and Ribbon layers. Then Choose Layer > Merge Layers or press Cmd+E (Ctrl+E).
In this document, the Texture and Ribbon layers are joined into one new layer. Photoshop kept the name of the top layer. You can double-click the name field and rename the layer.
Photoshop CS or earlier: Select the first layer, then click in the link column next to the other layers you want to select. For practice, select the Texture and Ribbon layers. Then choose Layer > Merge Linked or press Cmd+E (Ctrl+E).

Flattening an Image

If you want to merge all of your visible layers and discard all layers with visibility disabled, you would choose Layer > Flatten Image. However, flattening an image is a permanent change. You work hard for those layerskeep them! Here are some alternatives to flattening that will preserve future flexibility:

Save a copy of your image in a flattened format. By choosing File > Save As (with the As a Copy box checked) or File > Save for Web, you can save another version of your image.
If you need a flattened copy to paste in another document (or within your current document), use the Copy Merged command. Select an active, visible layer, then choose Select > All. You can copy all visible items to your clipboard as a single layer by then choosing Edit > Copy Merged or by pressing Shift+Cmd+C (Shift+Ctrl+C).

Tip: Flattening Images

Remember, flattening is permanent. Be 100% positive before you discard your layers permanently. Saving a flattened copy is usually a better idea.