Erratum: At 05:44 in the video, File > Script > Layer Comps To Files, is changed to File > Export > Layer Comps To Files. See Export layer comps.
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.
A layer comp is a snapshot of a state of the Layers panel. Layer comps record three types of layer options:
Layer visibility—whether a layer is showing or hidden.
Layer position in the document.
Layer appearance—whether a layer style is applied to the layer and the layer’s blending mode.
Note:
Unlike layer effects, Smart Filter settings cannot be changed across layer comps. Once a Smart Filter is applied to a layer, it appears in all layer comps for the image.
A. Apply Layer Comp icon B. Last Document State C. Selected comps
-
To view a layer comp, you first need to apply it. Click the Apply Layer Comp icon
next
to a selected comp.To cycle through a view of all layer comps, use the Previous
and
Next 
buttons
at the bottom of the panel. (To cycle through specific comps, first select
them.)To restore the document to its state before you chose a layer comp, click the Apply Layer Comp icon
next
to Last Document State at the top of the panel.
at
the bottom of the panel. Consider a document with layer comps placed as a Smart Object within another document. When you select the Smart Object in the containing document, the Properties panel gives you access to the layer comps that were defined in the source file.
This feature lets you change the state of the Smart Object at a layer level without editing the Smart Object.
Certain actions create a state where the layer comp can no longer be fully restored. This happens when you delete a layer, merge a layer, or convert a layer to a background. In such instances, a caution icon 
appears next to the layer comp name.
-
Ignore the warning, which may result in the loss of one or more layers. Other saved parameters may be preserved.
Update the comp, which results in the loss of the previously captured parameters, but brings the comp up to date.
Click the caution icon to see the message explaining that the layer comp can’t be restored properly. Choose Clear to remove the alert icon and leave the remaining layers unchanged.
Right-click (Windows) or Control-click (Mac OS) the caution icon to see the pop‑up menu that lets you choose either the Clear Layer Comp Warning or the Clear All Layer Comp Warnings command.
in the
panel, or choose Delete Layer Comp from the panel menu.
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