Today’s Question: When painting on a layer mask [in Photoshop or Photoshop Elements] where I am trying to completely protect an area, I sometimes use a selection tool to only select the area I want to work on. This permits me to brush with ease and not worry about touching the protected area. Is this a procedure you ever use?
Tim’s Quick Answer: This is certainly a very helpful technique, and something I do in some situations, especially when the area where I need to clean up a layer mask follows a straight line.
More Detail: In most cases, if I need to create a layer mask that includes a straight edge I will have used a selection as the starting point for the layer mask. Alternatively, I might create a selection after creating an initial layer mask, and use the Fill command (found on the Edit menu) to fill the selected area of the layer mask with white or black as needed.
In situations where I need to work with precision to fine-tune the edge of a layer mask, I’m generally using a very small brush and am zoomed in very closely on the area I need to work on. Creating a selection in these types of situations could certainly be helpful, but I typically find that when I’m working in this way I am focused on individual pixels and therefore don’t gain a significant benefit from having a selection.
But again, there are certainly many cases where using a selection while painting to refine a layer mask can be very helpful. When you have a selection active, you can only paint within the area defined by that selection, even if you are painting on a layer mask. In this way, selections can be very helpful for protecting areas of the layer mask you don’t want to modify, while refining areas that need some additional work.