Today’s Question: When performing image cleanup work in Photoshop why do you use an empty image layer instead of a duplicate layer?
Tim’s Quick Answer: The primary benefits of performing image cleanup work on a new empty image layer rather than a copy of the Background image layer are reduced file size and a more streamlined workflow.
More Detail: In Adobe Photoshop the primary reason to use layers is to provide a non-destructive workflow. For example, by performing image cleanup on a separate layer you are not altering the underlying Background image layer directly. This makes it very easy to then correct or eliminate any changes that ended up not working out well.
When it comes to image cleanup, you can either create a copy of a complete image layer (such as the Background image layer) or create a new empty image layer. The option for working with an empty image layer for this purpose is possible because most of the image-cleanup tools in Photoshop enable you to work across multiple image layers. For example, you can cleanup blemishes that exist on the Background image layer by painting on a new empty image layer, and the Background image layer can be used as the basis of the pixels created on the cleanup layer.
If you duplicate the Background image layer, you are effectively doubling the base file size. So, one of the key benefits of using an empty image layer for image cleanup is that the file size won’t increase significantly at all.
In addition, working with a separate image layer provides more flexibility in your workflow. You can easily erase pixels on the image cleanup layer if some of the cleanup steps didn’t work out as well as you would have liked, for example.
In general, I don’t recommend creating a copy of the full Background image layer unless the task you’re performing requires that step. This might be the case for certain filters or creative effects, for example. However, it is not necessary to duplicate the Background image layer for most image-cleanup tasks.