Today’s Question: Sometimes I don’t realize that I forgot to invert my selection [in Photoshop] until after I’ve added an adjustment layer, causing the layer mask to be the opposite of what I meant. Is there an easier way to fix that instead of using the Undo command to take a few steps back so I can invert the selection and then add the adjustment layer again?
Tim’s Quick Answer: Yes! You can simply invert the layer mask to reverse the area of the image being affected by an adjustment layer.
More Detail: I actually prefer to perform most of my work on a layer mask rather than a selection, in large part because this approach enables you to evaluate your work based on the actual effect in the image. Therefore, I often invert a layer mask for an adjustment layer rather than inverting the selection originally created as the basis of that layer mask.
A layer mask is really just a pixel-based image used in a different way compared to “normal” pixels in a photographic image. As such, you can use all of the various tools within Photoshop to alter a layer mask just as you would an image. In this case, for example, you can simply invert the layer mask to reverse the area being affected by a targeted adjustment.
The first step is to make sure that the layer mask is active, which you can do by clicking the mouse on the thumbnail for the layer mask on the Layers panel. Then simply use the Invert command to invert that layer mask. You can, for example, choose Image > Adjustments > Invert from the menu. You can also press Ctrl+I on Windows or Command+I on Macintosh as a keyboard shortcut to invert the currently active layer mask.