Detail of A Post-Truth World

Photoshop’s Merge Command

So many secret handshakes in Adobe Photoshop

Not long ago someone posted on a forum that he was having difficulty with Photoshop’s Merge command. It wasn’t behaving as he expected it to. In the course of helping the poster troubleshoot, I found myself going over the different ways the Merge command is invoked, producing very different results depending upon the state of the layers that are being merged, as well as the modifier keys we use to invoke a Merge command. I thought it might be helpful if I posted a summary here.

To avoid some of the massive confusion about these commands, which have been given a variety of names, I’m relying on the name of each command the History panel uses. The History panel produces a legal document and has to differentiate between each of the Merge commands. When it was developed, these are the names it used. These aren’t necessarily the common names people have used over time, but they are the names I think we might do well to adopt to avoid confusion. To follow along, open the History panel (Window> History) and look at the current state right after invoking one of these commands. I kept the graphic as simple as I could to avoid even more complication.

Cmd-E: Merge Down: This is the primary Merge command which merges the selected layer to the layer immediately beneath it. Layers that don’t allow you to merge a layer into them include Smart Object, Video and Adjustment layers. Vector Shape layers can’t merge into other vector Shape layers, either. However, all of these layers except Video can merge into a normal image layer, whether or not the bottom layer includes transparency. If a mask is present on the bottom layer, a popup message will ask you how you want to handle the mask.

Cmd-Shift-E: Merge Visible: This will merge all visible layers, but it will behave differently depending upon whether or not the bottom visible layer is a Background layer or not. If the bottommost layer can contain transparency (Layer 0, for instance) all the layers are merged without duplicating them into the topmost visible layer. If the bottom layer is a Background layer, it will merge all visible layers to the Background layer without first duplicating them.

Layers and History panels showing results
If the visible layers do not include a Background layer, the layers will merge without being duplicated into the topmost selected and visible layer (left). If the visible layers you’re merging include a Background layer, the visible layers will merge into the Background layer (right).

Cmd-Opt-E: Stamp Layers: Stamp is another way of saying “make a copy of the layers and merge it onto a layer.” This is not found in the Layers menu or in the Layers panel menu It is one of Adobe’s many secret handshakes. If all layers can contain transparency, it creates a copy of only the selected layers, and merges them to a new layer above the topmost selected layer. You don’t have to create a new layer first.

If the bottom selected layer is a Background layer, it merges a copy of all the selected layers to the Background layer, changing the Background layer itself, but leaving the other layers intact. This command is especially useful if you have a lot of layers, but only want to merge a very few­—rather than turning off the visibility for several layers, simply select those few you want to merge.

History and Layers panel showing command results
If your selected layers do not include a Background layer, Stamp Layers will add a new layer above the selected layers and stamp a merged copy onto that layer (left). If the selected layers do include a Background layer, the merged copy of all those layers is stamped onto the Background itself (right).
Detail from artwork showing Stamp Layers instance
This is a detail from a much larger document that had many layers. When I wanted to create a drop shadow for the two Xquizart figures, the easiest way to keep the original elements intact, but create a combined drop shadow, was to select the layers I wanted to copy with merge, and use the Stamp Layers command to place it above the original layers. I then turned off the visibility on the original layers, but if I decided at any time to change something, I still had access to them.
Layers and History panel showing instance of
This is possibly the most popular of the Merge commands. It copies, then merges, any visible layers into a new layer that it creates. The layer is placed directly above whatever layer is currently active. In typical use, you want that to be the top layer you currently have in the Layers panel, but not always.

Cmd-Opt-Shift-E:  Stamp Visible: Many people also call this command simply “Merge Visible,” but that doesn’t distinguish it from the actual Merge Visible command found in the Layers panel. This command doesn’t exist in either the Layers panel or in the Layers menu. However, if you hold down the Option/Alt key when accessing Merge Visible from the Layers panel, it will invoke the Stamp Visible command, which you can see reflected in the History panel state.

This popular, though hidden, command copies all the visible layers, merging them, and “stamps” the merged copy to a new layer above whatever layer is currently selected, even a Background layer. You don’t have to create a new empty layer with this command. It will make the layer for you. Of course, if only one layer is visible, Cmd/Ctrl-J to duplicate that layer is the better command.

I hope you find this helpful. Between the lack of menu commands and the variable ways they each behave, the commands can be frustrating. However, they’re worth memorizing. I most often use the Merge Visible and Stamp Visible commands, but there are definitely occasions where Merge Down and Stamp Layers serve my needs.

Full image for A Post-Truth World
A Post-Truth World is one in my Democracy series. When I created it, I added text at the top, then decided I wanted to run Topaz Texture Effects on the image— but without affecting the text or flattening any of the layers. I turned off the visibility on the closed Group text layer and targeted the layer beneath it before using the Stamp Visible command. Credits: itKuPiLLi, Priss, Lorie Davison, Holliewood, and many others.

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