Recently I've come to know about Layer comps. They are great way to create and save multiple variations of a document without having multiple files. Can anyone explain how to use/create them? How do they work and why they are useful?
What is Layer comp :
Layer Comps are a bit like "snapshots" of the Layers palette. It records the stacking order and visibility of each layer, as well as the layer styles and the position of the content of each layer in the image. It's not like the snapshot feature in the History palette since Layer Comps are actually preserved when you save your document and reopen it afterwards.
You can create as many as you like, without substantially expanding your file size.(such as making different PSD's for different color variants) You can recall a Layer Comp with an instant click. You can also export all variations to a multiple files or a single PDF presentation to send to a client to review.
Layer Comps are another way for you to manage your layers. Instead of having to create multiple documents to see variations in a project, you can use Layer Comps to manage your project.That is why they are helpful/useful.
Designers often create multiple compositions or comps of a page layout to show clients. Using layer comps, you can create, manage, and view multiple versions of a layout in a single Photoshop file From Adobe help guide
How to use them :
See a working example of Layer comp here...
Hope this will help....