Quote Originally Posted by Photo Engineer View Post
FYI, the same is true of silver halide crystals, and back in the old days they used to judge the extent of ripening by the color of a small sample viewed on a glass slide. The color varied from yellow through green to red, but ended up being obscured when they began using varying amounts of iodide as it gave a strong yellow to red tint to most all crystals.

PE
Yes this is true, and everytime you wash out your equipment (in the light) one can observe colors.

Ron, were they still doing this when you began?

When do you think it totally ended?

I always wondered about this, it is mentioned in both Wall and Baker I think, but (except for one ref I found later) details on how this was done in practice were vague... My hang up is I do not want to lose or fog any of my emulsion, so I could not figure out how one could differientiate between grey, blue, green, yellow and under the ortho-safelight (dark red) I use in my darklab)
Leaving the area did not seem practical to me... do you know how it was done at Kodak?

Did you sacrifice a coating on glass?
and if so, to what light source?