Excellent News, Michael! I will review the quantities and sizes I ordered and I will probably be sending you a check for some additional paper.
Everything is analog - even digital :D
Precisely my point.
Are you forgetting that a very substantial investment of money and time has been made in order to do this?
age and ripening of gelatine emulsions
i haven't touched a sheet of azo in twenty yrs -----BUT-
Originally Posted by PHOTOTONE
if azo was the last comercially made emulsion that was a modern child of the original gaslight papers(i dont know-ask photo engineer) then it was a formula that has dffernt aging characteristics than the modern emulsions which are full of restrainers that allow non-refrigerated storage
film emulsions must be refrigerated to retard age ripening which causes speed and contrast changes even in the newest emulsions
there are many people who are hand coating supports with emulsion formulas that are the same as the original gaslight papers that azo was emulating
these formulas are made when needed and aged to the state that is required for the specific end in mind-used fresh it is one speed and contrast- a 1 week ripening is more stable but dffernt and so on and so on
this pertains to the emulsion before it is coated, and also to the emulsion after it is coated on the support
this is usually a plain silver/salt gelatine emulsion-mostly uv sensative -and it may be modified with iodides and bromides-even the differnce between chrome alum as a hardener and potasium alum affect these ageing characteristics and the speed and contrast
i guess since this work is mostly done in countries that don't speak english that is why you folks are not aware of being able to make your own azo precursors and modify them to be azo if you wish
ask photo engineer-ron will tell all he knows
thanx for the time and attention
vaya con dios
I don't know much about technical details, but I do know that Kodak Azo had a good reputation for being good many years after its expiration date regardless of storage. There are documented cases of Azo being perfectly fine after decades of sitting around at room temperature in places with 100F summers. So, perhaps Azo incorporated restrainers, too.
on the mark
que tal juanito?
Originally Posted by juan
you are absolutely correct-i said that azo was "emulating" the previous gas lite papers--at least that was what i meant to say
i don't know what this new paper is but it shure sounds like a gelatine that has not been stable-ized by age in warehouse-i'm sure that they are doing a great job and are trying to make the best replacement they can for azo-it was wonderful stuf but its dead and gone
if we can interest pe in this thread ron will corrct me and we will all learn the real deal
i like to try to make people aware of the history of developement of materials--- and to try to make your own so you can always have what you need
i say go right to the gas light papers and roll your own like saul bolanyos
how's the glue? gooey? pm me i got some sources for ya
vaya con dios
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Any contact paper that will be made will only be Azo like paper, not Azo paper. It will not have the same tinted support, the same keeping, the same reciprocity and etc that Kodak had. It may be better or worse in any of these. IDK and I cannot predict.
Kodak had 2 Azo papers, made in two plants. This is not untypical.
pe-what were the differences if any-intentional/unintentional? between the 2 azo's?-i only remember that i liked the base tintand emulsion color
Originally Posted by Photo Engineer
like i said-its been 20 yrs-the same time i was using 20x24 ektaflex -
(for my personal work i was using the neg as the finished art)
i think i used more dupont and fuji films at that time tho-kodak was the winner in paper for final output
the holes in my head from last summer's crash and burn make me very frustrated
i dont think i know anyone who is trying to duplicate azo-just looking to get some of the nice features but that is a personal take on each and every aspect
support color and texture maybe more important to many artists than the emulsion
vaya con dios
All Kodak paper supports had pigment tints incorporated in them to give a certain tone to the product. Azo was not unique in this respect.
Kodak made Azo in at least two plants. IDK the details but the curves and speeds were slightly different due to the vagaries of making emulsions in different sites. I have seen this myself making my own Azo like paper in 3 locations.
PE, what was it about azo which made the age problem with many papers not a factor for azo? If the current (new) paper needs to age, did Kodak age its azo for some initial time period, then find it had levelled out and stopped changing? This is still confusing. The old azo does keep well (I still have a stash) and not change much, if at all, for many years. Why was this possible with azo, but a large problem with many other papers?
If the new paper needs to age after being manufactured, won't this also indicated that keeping properties over many years may be different than azo? tim
AFAIK, Kodak did not age Azo paper. It, like just about all products, was usable off the end of a coating machine. Otherwise, how could we make it. You have to have an aim, not a moving target. This is a common misconception in the photo community, that products age into a 'good' situation. They can be made that way but all to often, they keep going until they spoil.
In my time at Kodak, I know of two common situations where this did happen. Ektachrome Type "R" paper had bumps in the curve due to the use of 9 emulsions. Over 6 months the bumps evened out, but there was no gross change in speed or contrast. It did have a finite lifetime and needed refrigeration. In the second broader case, products hardened with formalin gradually lost speed and contrast and gained in fog. Otherwise they were stable for a few years and gradually went into fog due to heat and radiation as well as the formalin. We see the problems with heat and radiation in some products today.
If a product is built to change, it continues to change. There is no magic signal that goes off in the coating that says "stop today". If it is built to be stable, then it remains stable.
My own Azo type paper is identical the day I coat it and up to 6 months later. There is no significant change that I see. And, I'm not doing anything special except what is expected in emulsion making. I can make it more stable or less stable by treatments common to emulsion making and coating.
Without knowing the M&P emulsion formula, all I can say is that I have seen this type of behavior and found it due to either one of several possible conditions. But I would be guessing if I tried to diagnose it.