What causes these white dots? Are these considered fireflies?

Taylor-S-Rose

You can see them in particular in the shadow under the chin, on the chin, and on and around the lips.

Sometimes they show up and sometimes they don't.

The attached image is a super close-up and you can't really see them at full resolution, but I've zoomed in on other renders on Deviant Art and they don't have these white dots.

I thought that it might have to do with the render times (I rendered this image for 10 hours) but sometimes I'll render a piece for less time (8 hours) and the result will not have the white dots.

Richard Haseltine

I think that is noise - it's a shadowed area and so the light less frequently reaches it, meaning that when enough pixels have reached a settled values (Render Converged Percentage) for it to stop there is still a notceable lack of completion there.

Taylor-S-Rose

OK, that makes sense. I do notice that the noise tends to appear in darker areas, like shadows. I also noticed it during a render I did a couple of days ago with the Desert motel room -- there was a lot of noise on the walls, which are dark brown. Thanks Richard.