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the effects of aging on developers
This question may be a bit of a handful. My question concerns developers and
what are the effects on the print or film as the developing agents age. I know most, or I should say those that I use (powdered mix D-76 and Dektol and Selectol), say a shelf life of 2 months in a tightly-stoppered dark bottle is the limit and I follow that suggestion. But what I would like to know is what can be expected as the developing agents age. Are the effects uniform or do the highlights suffer first and shadow detail second or vice versa? I guess what I'm asking is if the component developing agents deteriorate at different rates. What happens if you go beyond the suggested shelf life. Is there some kind of compensation that can be made for the aging of the developing agents? I'm hoping to get replies based on obviously more knowledge, but also the breath of experience that others have in processing their own film and prints. All replies will be welcomed. Thanks! |
#2
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the effects of aging on developers
"Robert J. Mathes" wrote in message ... This question may be a bit of a handful. My question concerns developers and what are the effects on the print or film as the developing agents age. I know most, or I should say those that I use (powdered mix D-76 and Dektol and Selectol), say a shelf life of 2 months in a tightly-stoppered dark bottle is the limit and I follow that suggestion. But what I would like to know is what can be expected as the developing agents age. Are the effects uniform or do the highlights suffer first and shadow detail second or vice versa? I guess what I'm asking is if the component developing agents deteriorate at different rates. What happens if you go beyond the suggested shelf life. Is there some kind of compensation that can be made for the aging of the developing agents? I'm hoping to get replies based on obviously more knowledge, but also the breath of experience that others have in processing their own film and prints. All replies will be welcomed. Thanks! Stock, unused, D-76, Dektol, Selectol, etc., should have a minimum life of about 6 months in a filled, sealed bottle. In a partly filled bottle its less. Kodak gives 2 months, but that is conservitive. If kept away from heat it should last longer. The main thing that happens to developer is oxidation. The oxidation converts part of the sulfite to sulfate and can oxidize the some of the developing agents. In the case of Metol the oxidized forms are not active developing agents. Hydroquinone oxidation products can be even more active than the base form. Packaged D-76 is buffered so there is little change in activity with time. The original D-76 formula rises in activity with time due to a slow reaction between the hydroquinone and sulfite. This produces some sodium hydroxide which raises the pH of the solution. Since the pH is fairly low to begin with it has significant effect over a period of perhaps a month. The buffered variety can handle the hydroxide so its pH stays constant. The same effect takes place in all hydroquinone developers but Dektol, for instance, so much higher in pH than D-76 that the effect is masked and is of no significance. M-Q developers, like Dektol and D-76, and most Phenidone developers, are quite stable with time. Some developers, in particular Amidol and some Pyro formulas, are not at all stable and have a very short lifetime once exposed to air. Pyro can be protected by additions of Sulfite and Metol, but, if enough sulfite is added to give it long tray or tank life, it looses its staining and tanning properties since these are due to oxidation products and the sulfite prevents them from forming. I have had packaged D-76 stay good for a year after mixing (I don't recommend this) and Dektol for rather longer than the advertised time. Dektol starts out straw yellow and becomes progressively browner as it ages. If its quite brown toss it. Eventually, if they become oxidized enough, hydroquinone developers will develop a very offensive odor. -- --- Richard Knoppow Los Angeles, CA, USA |
#3
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the effects of aging on developers
"Robert J. Mathes" wrote in message ... This question may be a bit of a handful. My question concerns developers and what are the effects on the print or film as the developing agents age. I know most, or I should say those that I use (powdered mix D-76 and Dektol and Selectol), say a shelf life of 2 months in a tightly-stoppered dark bottle is the limit and I follow that suggestion. But what I would like to know is what can be expected as the developing agents age. Are the effects uniform or do the highlights suffer first and shadow detail second or vice versa? I guess what I'm asking is if the component developing agents deteriorate at different rates. What happens if you go beyond the suggested shelf life. Is there some kind of compensation that can be made for the aging of the developing agents? I'm hoping to get replies based on obviously more knowledge, but also the breath of experience that others have in processing their own film and prints. All replies will be welcomed. Thanks! Others here can answer your question much better, but the _very_general_ answer is the developer activity decreases with age. Black areas will not develope fully. You will get less contrast. If you _absolutely,_positively_ had to use some old developer, I'd increase the developer time, perhaps by 25-50%. As for the 2-month shelf-life, I prefer the guideline: "If it's brown, flush it down". Ken Hart |
#4
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the effects of aging on developers
"Ken Hart" wrote
If you _absolutely,_positively_ had to use some old developer Reference for information: "Lootens on Photographic Enlarging and Print Quality." Available from Abebooks and Amazon for $1.25 and up, a bargain. In the old days, old developer was used 1:1 with fresh developer to shift warm tone paper farther towards the warm end. I can't say I have tried it, as my warm-tone paper stock went with the use of the last of my Agfa Portriga (?). WBUAT: Is there a modern equivalent of the old warm tone papers among all these Bergers and Kentmeres and Rajahs ... There was also advice to add Sodium Carbonate to old developer to revitalize it. Somewhere around 1/2 oz Na2CO3 to 32 oz shot developer. -- Nicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. |
#5
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the effects of aging on developers
"Nicholas O. Lindan" wrote: "Ken Hart" wrote If you _absolutely,_positively_ had to use some old developer Reference for information: "Lootens on Photographic Enlarging and Print Quality." Available from Abebooks and Amazon for $1.25 and up, a bargain. In the old days, old developer was used 1:1 with fresh developer to shift warm tone paper farther towards the warm end. I can't say I have tried it, as my warm-tone paper stock went with the use of the last of my Agfa Portriga (?). WBUAT: Is there a modern equivalent of the old warm tone papers among all these Bergers and Kentmeres and Rajahs ... There was also advice to add Sodium Carbonate to old developer to revitalize it. Somewhere around 1/2 oz Na2CO3 to 32 oz shot developer. -- Nicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. All I can say is I'm 76 years old and still developing. Sorry, I couldn't resist. |
#6
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the effects of aging on developers
Patrick Gainer wrote in news:401464B3.E13201D7
@rtol.net: There was also advice to add Sodium Carbonate to old developer to revitalize it. Somewhere around 1/2 oz Na2CO3 to 32 oz shot developer. -- Nicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. All I can say is I'm 76 years old and still developing. Sorry, I couldn't resist. With sodium carbonate??? ((-: Jorge |
#7
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the effects of aging on developers
Jorge Omar wrote: Patrick Gainer wrote in news:401464B3.E13201D7 @rtol.net: There was also advice to add Sodium Carbonate to old developer to revitalize it. Somewhere around 1/2 oz Na2CO3 to 32 oz shot developer. -- Nicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. All I can say is I'm 76 years old and still developing. Sorry, I couldn't resist. With sodium carbonate??? ((-: Jorge Sometimes a little wine helps. Pat |
#8
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the effects of aging on developers
Thank you all for your replies. They have all helped..........except for the
76 year-old's, that is! bob mathes |
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