Layer Comps
Imaginethat you want to have three versions of your project. The first version should have a red background and some buttons at the top. The second version should have a green background and the same buttons on the bottom. The third version should have a blue background and the same buttons on the side. Each background and each button is in a separate layer.
One way to do it is to prepare the first version and put it all into a new folder. Thenyou can duplicate the whole folder of layers and prepare the second version (rearrange buttonshide the red background and unhide the blue background). Then you can duplicate one more time and prepare the third version.
Such approach has many disadvantages. If you decide to edit one of buttonsyou would have to edit all three copies of it. Duplicate content also makes PSD files larger.
What is Layer Comp?
The layer comp is an objectwhich stores "the state" of a PSD document. Preciselyit stores the visibilitythe position and the appearance (opacityblend modelayer ) of each layer.
To solve the previous taskwe could arrange layers in all three ways and create a Layer Comp for each arrangement. We can switch between layer comps later. Switching layer comps performs the change of visibilityposition and a to a previously stored value in a signle click.
Each layer comp has the name and three flags: VisibilityPosition and Appearance. Each flag can be enabled or disabled. When some layer comp is activatedthe change will be performed according to these flags.
For exampleyou are making a collage with animals. You want to be able make only birds visible. Alsoyou want to be able to make only brown animals visible. Splitting animals into three folders BirdsBrown and the Rest is not possible (because some birds are brown). You can create layer comps Birds and Brownand enable just the Visibility flag on these comps. Laterif you move animals around and switch to Birdsonly the visibility of layers will be changed, while the position (an the ) will be preserved.
Layer Comps Panel
Management of Layer Comps is available through the Layer Comps panel. You can open that panel using Windows - Layer Comps.
At the topthere is the Last Document Statewhich stores the last document state. Each item has the Apply button on the left. The button contains a checkmark ✓ when that layer comp is applied or the dash otherwise. You can switch between layer comps (or the last document state) by clicking this button.
You can select layer comps in the panel by clicking on their nameswithout actually applying them. Once a layer comp is selectedyou can delete it by clicking the bin buttonor update it by clicking the update button. You can also create a new Layer Comp by clicking the New button.
You can rename any layer comp by double-clicking its nametyping a new name and hitting Enter. Each item also has three buttonswhich you can use to switch the VisibilityPosition and Appearance flags.
When you apply a specific layer comp and then start editing the document the current state (created by the Layer Comp) will become the Last Document State and all your changes will be performed within that Last Document State. If you want to make changes to some Layer Compedit the document first (inside the Last Document State), then select the comp in the panel and press the Update button.