I have found that the bleach sepia attacks highlights first
also selenium attacks the shadows first.
If you selenium too long first I believe the bleaching and sepia will be less effective, though it may give a look which is appropriate for some taste.

I always start with the highlights, and I do not go too deep into the midtones, therefore not affecting the shadows, which I then hit with 1:5 selenium to taste.

different papers will need different times in the bleach and selenium.
Warmtone less than coldtone papers.
Quote Originally Posted by MaximusM3 View Post

Question: if one wants to use thiourea to achieve the same effect, I guess it would be better to do strong selenium first to protect shadows, then bleach + thiourea? Then again, strong selenium may leave nothing to bleach out..