I generally let the lenses stay under for at least 24 hours. Not sure if this is more for peace of mind, but it seems to have worked for a few lenses from years ago and is what I did for the last batch of lenses.
UV-C is too deep into the non-visible, does not penetrate the glass. UV-A and UV-B lamps penetrate glass enough to clear radiation-damaged Thorium glass lenses.
Yellowed glass= A Pentax Super-Tak too about 3 days.
UV-C is too deep into the non-visible, does not penetrate the glass. UV-A and UV-B lamps penetrate glass enough to clear radiation-damaged Thorium glass lenses.
Yellowed glass= A Pentax Super-Tak too about 3 days.