sparrow6224
Well-known
I read in some other forum an aside, as part of a minimally related discussion, someone remarking that Diafine is a commercial version of Divided D-76. Tom -- or anyone else -- is this true?
Tom A
RFF Sponsor
That is a new one for me! D76 is a developer that was designed in 1926 and, at that time, primarily used for movie stocks. The high volume of Sodium Sulphite gives it a softer definition than Diafine does. I dont use Diafine as a rule - tried it and did not like what it gave me. I have not seen a chemical analysis of it either.
Divided D76 is similar to regular D76 - except that the developing compound (metol) is allowed to saturate the film without really doing much - once you add the B bath (Borax or Kodalk) - it activates the developer.
One reason why i doubt the Diafine as being a variation of Divided D76 is that standard Divided D76 is truly lousy at "pushing" film speed.
There are divided developers that can be used for pushing, at least moderately, like Stoeckler with the B bath substituted with Hydroxide rather than Borax/Kodalk.
Would be interesting to find out if any one can put some light to this.
Divided D76 is similar to regular D76 - except that the developing compound (metol) is allowed to saturate the film without really doing much - once you add the B bath (Borax or Kodalk) - it activates the developer.
One reason why i doubt the Diafine as being a variation of Divided D76 is that standard Divided D76 is truly lousy at "pushing" film speed.
There are divided developers that can be used for pushing, at least moderately, like Stoeckler with the B bath substituted with Hydroxide rather than Borax/Kodalk.
Would be interesting to find out if any one can put some light to this.
skahde
V for Victory!
Neither from the recipe nor from its actual influence on the result. Where divided D76 will only slight alter the desitometric curve, diafine will give a remarkabel increase in speed.
sparrow6224
Well-known
It seemed unlikely to me.
Freakscene
Obscure member
No. Diafine has a lot of phenidone in the A bath and the B bath is very alkaline, probably sodium carbonate and possibly some hydroxide. Divided D76 has no phenidone and most formulae recommend metaborate for the B bath, although any of the photo alkali will work, including borax, carbonate or hydroxide.
Marty
sparrow6224
Well-known
In researching this earlier this evening, I came across the M-whatever sheet and sodium carbonate is the main active ingredient in the B solution. On a Flickr discussion group of divided developers one crusty fellow recommended using the A bath, with a Borax (DD-76) B bath, and using the Diafine B bath to clean your oven. I guess he felt it's a little harsh.
Freakscene
Obscure member
Good one. The oven cleaner we use contains a lot of potassium hydroxide and is pH ~14 (it's hard to reliably measure the pH of something very alkaline or acidic with what I have at hand) - the Diafine B bath isn't quite that alkaline.
In my experience if you use metaborate, borax, or carbonate as a B bath in a given divided developer, the differences in results are detectable by sensitomitry but are very, very subtle, to the point of being hardly noticeable. You can't use much hydroxide before you start to cause problems, so I never tried it, but I bet all you would get by using it is ever so slightly more contrast and faster development.
Divided developers make less difference with modern films than those from the 1960s and before, and mostly aren't worth the bother, particularly because of the inevitable compression in the middle tones that the process creates.
Marty
sparrow6224
Well-known
I have been stand developing everything from Acros to Tri-X to TMY to Neopan 1600 in Rodinal 1+100. 60-75 minutes, one gentle agitation or two equally spaced. Tri-X fares best, but HP5 and Acros also look great. I assume, in my relative naivete, that this, as with a divided developer, has a compensating effect. No flatness of contrast though.
Freakscene
Obscure member
Stand development in Rodinal is meant to be compensating, but in practice with modern materials the compensation effect with any process is pretty minimal, certainly in comparison to what you could achieve with Super-XX or other old style thick films.
The current fashion for stand development with Rodinal is interesting. Leaving the film in there that long isn't doing anything - the dilute Rodinal is completely exhausted by ~30 min at the longest, and in many cases after 20 min. But the extended development isn't doing much harm either, so if it works for you, no problem.
Divided development doesn't cause flatness of contrast - you still get a full range of tones - but the mid tones are more closely spaced than with other development systems. This is "midtone compression".
Marty
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sparrow6224
Well-known
So that the overall effect is there being a predominant sense of more middle gray? One tone not standing out from another, mushing together into what appears to be one tone? I call that flat looking but perhaps I'm using the wrong parlance. Nomenclature. Idiom. Jargon. Terms of art. Etc. Actually I shall research midtone compression and look at examples if possible and then I'll know if what I'm thinking of is what you are talking about.
Freakscene
Obscure member
What you'll see is a lack of tonal differentiation in the middle tones, where if you developed by a more normal process you'd get differentiation. So the middle tones are "flat" but the whole negative has normal contrast from deep black to bright white, but the middle tones don't differentiate.
Marty