Empty Adjustment Layers

cletus

I came across an interesting trick - Empty Adjustment Layers. I looked around and although the technique has been around a while, it hasn't been brought up here, at least that I could find.

There are a few techniques out there that involve making a copy of your image onto a new layer, changing the new layer's blending mode (multiply, screen, etc...) and then adjusting the opacity of the new layer to get a desired result. Gefillmore's seamless panorama thread contains an example.

Instead of making a duplicate of your image on a new layer, add an adjustment layer on top of your image. Any adjustment layer will do. When the adjustment layer dialog opens, don't make any changes to the image. Just press Ok. Once the dialog closes, change the blending mode of the adjustment layer and adjust the opacity just as you would have with the duplicate layer method. You should see the same results as you would with the duplicate layer.

So why would you want to use the empty adjustment layer instead of the duplicate layer? Two reasons:

1. You can change the image under the empty adjustment layer and the blending mode/opacity settings will apply to your changes. With the duplicate layer method, you either have to make your changes to both the original image and the duplicate layer, or scrap the duplicate layer, make your changes to the original image, make a new duplicate layer and redo your blending mode/opacity adjustments.
2. File Size - Adding an adjustment layer shouldn't increase the file size as much as adding a regular layer would.

cletus

cletus wrote:

2. File Size - Adding an adjustment layer shouldn't increase the file size as much as adding a regular layer would.

I ran a quick test to see if the file sizes were different. I started with a flattened 1336 x 903 pixel image. The duplicate layer method resulted in a 7.01 Meg PSD file and the empty adjustment layer methed resulted in a 3.56 Meg file.

DavidTO

I love this tip!