Quote Originally Posted by Konical View Post
The only significant reason to use selenium toning on MGIV
is that it might, just might, add to the archival qualities of
the paper, and even that seems subject to debate.
The IPI has cast doubt upon the effectiveness of selenium
contributing in any way to the LE of prints. If the selenium
is contaminated with sulfide there is a much better chance
of greater LE; Life Expectancy.

All the while testing microfilm, they did find a 1:9999
dilution of sodium sulfide to be completly satisfactory
in extending LE. Dan