OK, I think we'e about run this thread into the ground. Here's my final
contribution. Last night I reprinted a neg that I'd done a few weeks
ago. Made two identical prints (fairly easy to do with divided
developer--gives almost 100% repeatability). One of them I processed
through several soaking washes not totaling more than 1 1/2 hours from
beginning soak to ending soak. The other, I left in overnight, and then
squeegeed it and put it on the drying screens. I cannot tell the
difference between the two prints visually. Both were done on Agfa MCC
111 (glossy, air dried). So my "totally scientific" conclusion is one
of two possibilities:

1. Even a very rapid soaking wash process leaches out the brighteners
(4 changes of water over a 1 1/2 hour period), OR

2. The brighteners don't leach out.

The highlights are crisp and creamy, gradations are delicate, the tones
aren't muddy, blacks are gutsy, and I'm happy with the look.

So until I can see a difference, I'm not going to worry about it.

Larry

Jean-David Beyer wrote:

wrote:

Jean-David Beyer

I think the UV consideration a bit trivia. So, whatever it is,
it will fluoresce in the very deep blue. I don't think it has
anything to with whitening/brightening. Personally, I don't
think I can see light at those wavelengths; 427-430nm.


My guess is that if you can see through a #47B filter, you can see 430
nm, because that is where its peak response is. The peak response Dr.
Henry got was in the 427-430nm range. He did not say there was no
other response. For a brightener to appear white, it would need some
response at longer wavelengths, perhaps. But in any case, since the
paper is excited also in the visual range, the brightener probably
just makes the reflected light slightly brighter and slightly bluer.

While I doubt quinine is what they use, you can sure see that quite
easily when it is excited with long wave ultraviolet bulbs; it looks
white - ever so slightly blue.

Everybody in this business knows the 'much ado about nothing'
the industry puts forth. My guess; many years ago some modest
change in coating of papers was made and, of course, the
much ado followed.


They put brighteners in laundry detergent. I do not recall any of it
claiming that, but some clothes "glow in the dark" when illuminated
with long wave ultraviolet. In the 1960s it was easy to see at disco
places. They do not make much ado about it: they just do it.

If Dr. Henry can't tell us of those coatings' composition we'll
have to ask those who coat there own for some information.


Dr. Henry is not likely to put out a third edition to his book, so we
should not expect new information from him. Those who coated the paper
when he wrote the second edition to his book refused to tell him what
they used. I doubt they will be anymore forthcoming these days. Now if
you know private individuals making their own silver-halide printing
paper emulsions, they can perhaps tell you what sizing they use (if
any), but no one will tell you what the major manufacturers use.

There
are likely a few with the information. As for going to the very
sources them self of the paper and it's pre-gelatin treatments
we may be out of luck; propriatory information. Dan