Paper developer lifetime?

[Maine-iac]

That sounds like a really interesting method. How do you repeat a print when printing at a later date?
Murray

Actually absolute repeatability and consistency from print to print is one of the reasons divided developers were, uh, developed.

In the Dektol variant I use, nothing visible happens in Bath A, since there is no alkaline activator. The latent image simply soaks up however much of the developing agents as needed. In Bath B, the soaked up developing agents develop to exhaustion very quickly (under a minute) and then stop. When it's done, it's done. No further development can take place.

I understand from Ryuji and others that modern papers do this pretty well in one-solution developers, and that it's not as easy to leave a print in the developer for a longer time to increase contrast and density as it once was. My initial experiments with his DS-14 formula indicate that this is correct. As a one-solution developer develops more prints, however, it stands to reason that it loses some potency, say between the second and the twentieth print. Replenishment can address this, but with the divided developer, it's automatic. Bath A does not lose potency. Bath B eventually becomes exhausted, but as long as it is still working, it will develop to completion all the agent absorbed in Bath A.

I've written a longer article and given formulas in the Chemistry Recipes section of this forum.

Larry

 

[MurrayMinchin]

l've written a longer article and given formulas in the Chemistry Recipes section of this forum.

Thanks, just read it...cool concept

Murray

 

[hortense]

I spent some time searching the archives without much luck (however I am always amazed at the info that a search dredges up!!).QUOTE]
To whit, I use the “emergence time” to estimate the status of my print developer. After my developer is “tuned up”, I note the time it takes for any perceptible image to show. I file this in my head. When the emergence time get too long, I figure my developer is starting to “poop out”. Typical example would be early on emergence time of say 35-seconds. After several prints have been dragged through the soup, I might start seeing it creep up to 45-seconds. As the developer continues, the emergence time will slowly increase. I make a judgment call and dump my developer (or tweak it with a little more unused developer).
Some photogs get more precise and use a “Factoral System”. For those interested in his system, you’ll find it in Eddie Ephraum’s book, “Gradient Light - the art and craft of using variable contrast paper”, published by AMPHOTO.