Chapter 12. The Flexibility of Layers

Pulling a rabbit out of a hat is one of the ways that magicians prove their sophistication and skill. Far more often than rabbits get pulled out of hats, layers pop up whenever you create an image in Photoshop, a vector graphic in Illustrator, or a document in InDesign just look at the application's Layers palette for proof! As a creative professional, you show off your sophistication and skill when you use well the powerful tool of layers.

Layers act like pieces of clear acetate, stacked one on top of the other, on which you can place pixels (in Photoshop) or objects (in Illustrator or InDesign). As you work, you can create, move, edit, and delete layers, for great flexibility and efficiency.

As we'll discuss in this chapter, creating multilayered files in the Adobe Creative Suite applications serves many purposes:

• In Photoshop, layers are your primary way of creating and managing complex compositions, allowing you to control the visibility, position, transparency, and effects applied to different parts of the composition.

• In Illustrator and InDesign, layers let you organize complicated documents, allowing you to separate dozens or hundreds of objects or groups.

• In all these applications, you can use and share layers (and in Photoshop, layer comps) to create different versions of artwork or pages. A designer can use versioning to produce alternative compositions as artwork progresses through the approval cycle. A production artist can use layers to produce different editions of the same file, targeted to different audiences.

This chapter discusses how layers work within Adobe Creative Suite applications, with the focus primarily on Photoshop, Illustrator, and InDesign and the similarities that make it easy to switch between these applications and share layers. (GoLive can create HTML layers, but we don't discuss them in this book.) For example, you can move artwork between Photoshop and Illustrator and retain as much of the layer structure as possible, along with the editability of type, masks, and other elements. You can control which layers and layer comps in Photoshop PSD and PDF files are visible in InDesign and Illustrator. We also touch on layer features in Acrobat and differences in how the Creative Suite applications handle layers.

Behind the Scenes: Layers the Old-Fashioned Way

Graphic artists who started their careers using computers to create artwork and layout pages may be mystified by the reference to acetate layers. When Steve and Sandee began in the field, layouts were created on mechanicals camera-ready paste-ups of artwork. Type and line art would be placed on one piece of artboard and would be shot with a process camera in preparation for platemaking for the printing press. When artwork needed to be shot separately (like artwork to be printed in a second color or an alternate version of text) it was pasted on an acetate sheet laid over the artboard and registered with the base artwork. These acetates were the predecessors of today's computer layer technology.