Thanks for sharing your experiments with BZ and expired color paper! The benchmark, SupraII exposure, to my eyes at least, has an unacceptable amount of base fog. It looks like at least 5cc of yellow and a few cc's of red over what should be a clean white. The agfa examples serve to demonstrate just how poorly color papers age (this stuff must be at least 10 years out of date). Most remarkable to me is the last example, expired ultra with BZ. Here you're very close to a base white. The exposure appears a bit heavy and I'm assuming that the color density is suffering a bit because of it. Did you have to print it down in order to get a proper black? But the difference between Ultra with BZ and without is astonishing. I'm surprised that you regard the non-BZ Ultra as having more accurate color than the BZ Ultra as, of the five examples, #4 (non BZ ultra) appears to me to have the worst color of all.
Again, thanks for your hard work and concrete examples - these kind of posts make APUG worthwhile.
Yes the 'terrible, attic-stored' paper came out best, as long as you use the BZ. But you would be shocked to know how much enlarger exposure this required because of the underdevelopment. I will say again, Kodak papers age gracefully and respond well to BZ. As far as my assessment that there is 'more accurate color' with the Ultra NOT having BZ: I had wanted to make the point that when using BZ there is oftentimes an inability to get rid of the blueness because of the necessary underdevelopment. If you look very carefully at the print you will see an accurate rendition of color, in terms of hue inter-relationships, but this involves mentally 'removing' the ugly green cast.
The 'benchmark' is really good paper. I did not use ANY BZ. I should have used a bit and with only a little there would have been NO yellowing or sufficient under-developing to cause blueness. This yellowing used to drive me nuts, even back in the 70s when I used to buy color paper before RA4 came out. I think that it was Ektaprint C. I used to buy it from Olden Camera in Manhattan in person and you know that their turnover was constant. Yet...if you looked closely at the new paper after processing, you would have seen, even then, with brand new paper, a slight buff in the white. How I wish that there was a chemical that could cause all densities to 'retreat' like Farmers Reducer does for B&W.
The Agfa Sensatis paper's colors are fantastic (possibly the best I have ever seen) when the paper is new. But this paper deteriorates quickly and I would not be surprised to discover that its long term image stability might be profoundly bad. - David Lyga
There is no connection between sensitivity stability and image dye stability I can think of.
Originally Posted by David Lyga
thanks for the efforts, I found those tests enlightening too.
Thank you EdSawyer: It was not difficult to do but very, very tedious.
AgX: You know, there just might be a connection even though I cannot provide a theory attesting to such. My experience with Agfa paper is that way, even the old fibre-based one that I used to buy in the 70s from Freestyle Photo (Type B chemicals they used). The colors were spectacular when the paper was new but both the sensitivity (age-fog) failed (preventing pure white from being able to be attained) quickly with time and also the final image deteriorated with years under merely tungsten room light. There certainly seemed to be a connection.
Now, having said all this, I tested yet another batch of Agfa Sensatis from my refrigerator. Years ago, about 2006, I bought about 10 ROLLS of paper of various manufacturers, that was real cheaply sold then, from various advertisers. It was a monumental task to cut all this with my paper trimmer but I actually did and it took about 50 hours or more to accomplish this. I purchased about two hundred black bags from Freestyle and each batch of color paper that I cut (each batch was about two hundred 5x7s) got double bagging for safety. Naively I thought that my color paper worries were over for the rest of my life. NOT SO, as you can see. False ecnonomy can play tricks on one's mind.(At least my ability to store food was severely truncated, but eating is not so important to an idiot like David Lyga.) But... this other batch of Sensatis was tested last night and it tested perfectly: no age fog even though it is just as old, albeit a different batch. I cannot explain this but I will say that back in 2006 I tested everything that I put into my refrigerator and everything was perfect. I had tested some Ilfocolor a week ago and there was a medium, ugly, cyan fog. But, last night I tested another Ilfocolor batch and it was perfect. There seems to be no determinant as to what will keep and what will deteriorate. Even B&W paper has people flummoxed as to what will happen. I have bought ancient, poorly stored B&W paper that had to be 50 years old and it was PERFECT! Other, much newer and better stored paper, went bad very quickly. I wonder if there is more to the aging of gelatin than we are led to believe. - David Lyga