I've been trying to figure out how to do this for years.
I have one layer that's perfect. I want to bring in another layer and align it to the first layer -- but I don't want that first layer to be altered at all. I just want the new layer to auto-align to the existing layer.
I cannot figure out a way to do this, and I've searched and googled and come up empty handed.
Can this be done?
Have you tried locking the layer that you don't want to move?
Many times, and it has no effect. The locked layer is still resized during an Auto-align action. Hence my puzzlement.
Are you sure? When I try it here the canvas is extended to accommodate the new layer but the locked layer is not distorted. The crop tool can then be used immediately after align to crop back down to the original image size based on the untouched layer.
I've tried that many times but never gotten it to work. I'll try it again now.
Can't get that to work. When I select Auto-align from the Edit menu with two layers selected, one locked, the two layers are aligned, and the locked layer ends up unlocked and altered. I've tried this with a layer that's locked as a background, and by locking a layer manually from the layer menu.
Now I think you're probably right! I thought the locked layer was being shrunk because I could see that the canvas was enlarged, but I may be completely wrong about that. The original image remains the same and only the canvas changes on that image (as the other layer is altered).
If in doubt, try this test.
After aligning, turn off visibilityof the upper unlocked layer so you can only see the locked layer with its extended canvas. Use the crop tool to crop the canvas to the original size. Now drag another copy of the lower image above that locked layer and set blending mode to difference. If both are identical it will look completely black.
How can you get the image back to the original size after the canvas has been expanded? I have a long series I am attemptin gto align and want to be able to do them in sections aligned to the original image. Having to manually crop it back to the original size makes that impossible.
Just control-click the original layer and Image > Crop.
I have tried every combination of clicking and selection. Click on the image, click on the layer list. Nothing is ever selected and crop is never enabled. Shoud ctrl-click have just selected the full context of the original image on that layer? I can see that the size of the original layer is unchanged but can't figure out how to select it's boundaries.
OK; so i didn;t try everything. I wasn't clicking on the image in the list which did cause the selection. Thanks for your help.
I think locking actually does work, but I've been fooled all this time by the fact that the canvas is enlarged, which made me think the locked layer was being shrunk!
Thanks Barbara and Dave -- you were right all along.
I'd tried locking the layer, but as I mentioned earlier, because Photoshop expanded the canvas, I assumed it was altering the size and shape of the locked layer (also because Auto-align unlocked that layer).
But once I crop down to the original size of the locked layer, I see that it remains unchanged.
Thanks again. I can finally use Auto-align the way I want!