Against what most of us start out learning as good darkroom procedure--for consistent results use fresh chemistry--every once in a while I see references to aging chemistry.
Gordon Hutchings, for instance, in _The Book of Pyro_ writes that the A (pyro) solution in PMK benefits from age, and that he keeps a large jug of solution A in a constant stage of aging, and he back-blends some of the vintage pyro with each new batch of pyro.
Users of Harvey's 777 developer seem to have a very firm belief that the first batch of film is never as good as subsequent batches, kind of like the first crepe.
I think this is also said of some color chemistry in commercial processing, that the replenished chemistry provides better results than the original batch.
On the other hand, D-76 and ID-11 are known to give contrastier results with age, and most common developers just go bad as they oxidize.
Any theories, hypotheses, or views on what can be going on here? Anyone out there (intentionally) aging their chemistry, or have a good sense for why some kinds of chemistry might benefit from age?
AFAIK the main differences between aged and new devs is the bromide content (as a by product of the dev process). This may not apply to Pyro.
Since I'm a single shot user, I cannot comment on how significant are these differences.
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you can add dk 50 to your list
when i was doing all the lab-work &C for a portrait photographer in providence,
she would use dk 50 for "X" sheets of film ( always doing replenishment ) ... when it was time to mix new chemistry, i would be instructed "never to clean the sides of the tank" and to " leave about 1/3 of the tank" to mellow out the developer. when i asked her what the deal was, she said that if she didn't mix spent and new developer together, the contrast would be too much.
HC110 acts the same way. In my days of doing darkroom work for the local newspaper we used it with replenishment, and a fresh mix alway gave grainy harsher looking negs than a well aged batch did. Month old replenished dilution B is a very nice fine grain developer, not mushy like Microdol-X.
There would definitely be a bromide increase in developers used in tanks and replenished like 777, DK-50 and HC-110. One wonders then, why not add more KBr as a restrainer up front? I suppose from the manufacturer's point of view, this would decrease the life of the developer, but if you know you like it that way, it wouldn't be unreasonable so as not to have harsh results on the first batch, and then you could just keep replenishing.
Pyro is a one-shot developer, so bromide isn't the issue. It's something to do with the alchemy of aging.
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Depends on the developer and the associated breakdown and oxidation products.
With ID-11 and D-76 you can chemically buffer the developer so that the "as-mixed" activity is the same as the "aged" activity. You can also buffer DK-50 and HC-110 (Pat Gainer will likely be heard from on these subjects).
For the most part, I use 1 shot developers mixed from stock concentrates for maximum repeatability and predictability. Notable Exceptions are Ansco 130, Agfa 8 and Diafine.
Everything is analog - even digital :D
You can also add Pyro Triethanolamine to the list. Mix and use the working solution and top off with fresh developer.
I can offer a single data point for D76. I use D76 as a one shot. Last week I used the last of some three month old stock. I developed an HP5 test sheet (exposed thru a step tablet) in 1+3 at 68.0 F for 9 min. The HP5 test sheet yielded CI = 0.35. I got CI = 0.33 under the same conditions with fresh stock two days later. I don't have an extensive data set, but the CI with the new stock looks consistent with the last test sheets I developed with fresh stock. CI changes 0.020 per minute the way I process and I don't usually miss a target CI by more than 0.01, so I'm inclined to believe the observed difference was due to the developer not in how I was processing the sheets (hand agitated Jobo tank).
I was leafing through a book recently by a prominent portrait photog- the name escapes me...did lots of close up shots of craggy rock stars like Keith Richards, Iggy Pop, etc., very warm tone-
anyway the thing that struck me was the constant references to mixing his new print developer with "old brown" which I took to be old developer- anyone heard of this practice or know what the point of it would be for prints?
I'm so old I thought everyone knew this practice, though most probably no longer use it due to the proliferation of one-shot developers and the tendency to seek the characteristics of diluted developer. Hardly anyone uses reuses diluted stock, though replenished HC110 certainly would be such.