I am hobbyist user, so it's not a great deal if you cannot help me.
I am trying to stack several photos, but to have the opposite of "object removal using stacks". I have four photos taken from the same point with my two friends sitting at the table and exchanging position between each shot. What I want to achieve is to have each of them several times in the final image. If I use Median stacking, then almost everything disappears from the photo with only table remaining and some ghosting. So I need to use masking, but that's where it gets a bit complicated. I tried Outlier stacking but that produces some artefacts and needs a bit refining, for which I also need some masking.
For the stack I have live stacking checked.
So I guess the question is how to most efficiently create masks from and for each stack layer? I figured I would select part of the one friend on one photo, e.g. hand, head and part of the body, and then I would apply the resulting mask to all other photos in the stack. But I would need to add all masks for all body parts to all photos... So that makes it a bit daunting. Not helping is that when I Alt-click on a layer and start selecting using Flood select tool that the selection outline is shifted several pixels to the left in comparison to photo itself. Also, I cannot get the tolerance to right amount; it always selects something from the background or not enough of what I need.
Also, which blending mode would suit me the most?
Do you have some other suggestion how to achieve what I want?
P.S. I've found that if I stack only two photos and then use Standard deviation as the stack operator that produces black areas where the photos are the same and some type of blending in the areas where there are differences. That seems like a good starting point for a mask. How to create a mask from such stack result?