Diafine and Variable EI
This is my first time posting as I recently returned to film photography and just started B&W shooting for the first time. I have a couple of questions regarding Diafine film developer but first some preamble.
Diafine states that you can increase the EI of the film you are using with results comparable to the manufacturers stated EI (e.g. 160 EI for TMX 100). In addition, development times basically fixed and it allows for multiple rolls of film with difference EI ratings.
The questions are as follows:
Can you use different EI on the same roll without blowing out highlights or losing shadow detail? This is something IIRC you can do with Ilford XP2 Super.
Can you use the manufacturers state EI or are you "stuck" with Diafine's rating?
Thanks in advance for your responses!
Diafine is a divided developer, so you are more or less stuck with the EI that gives you the expsoure. Although Diafine is very forgiving I would do some testing with your equipment to fine tune your rating. I cant comment on XP2.
I think you'll have to try to match what you need for your printing. Diafine states EI 1600 for Tri-X for instance. I don't get enough shadow detail that way, and I like dense negs for printing, so I shoot at EI 800-1000. I tried TMX once in Diafine, and it's a 1.5 or so stop increase over the film's normal sensitivity of EI 50 (in most developers it seems), so it's significant. I didn't quite like the look of it however. Looked better in Rodinal for example.
But if you need a developer to do expansion and / or contraction developing then Diafine is probably your worst choice!
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The speed increases with Diafine tend to be overly optimistic. You really need to do your own tests with the film you use. I have found that divided developers are not very good for general use. A conventional developer is usually a better choice.
Most sensitometrists I have talked to (or read) say the same thing about divided developers in general. Several have said that with modern films, the effect of a 2-bath can always be duplicated with a single bath, diluted if necessary.
Originally Posted by Gerald Koch
On the other hand, I'd add that with a conventional developer the penalties for overexposure -- a stop or even two -- are trivial compared with the penalties for underexposure, so with a developer that gives +1/3 stop true ISO, overexposure shouldn't do much harm. A compensating developer is another animal entirely, but from past experience with 2-bath devs, over-exposure shouldn't do any more harm than usual (bigger grain, reduced sharpness).
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Diafine came out when film emulsions were still fairly thick and could absorb a fair amount of the first solution. I haven't used it for a long time, but I think present methods of stand or minimal agitation development are at least as likely to get the desired results. That's just an opinion, but the last time I compared D-23 with the D-23-borax split developer, the characteristic curves were indistinguishable. The extra step was not worth the effort.
It might prove something if one were to compare Diafine 2-bath with a mixture of Diafine A and B. If that one, which will not be I, got both characteristic curves to have the same contrast index, one might find everything else the same as well.
It won't hurt my feelings whichever way it turns out. Also, it probably won't make a difference in my personal practice. I get enought film speed by reading ths shadow and setting my meter at 4 times the box speed. This is what you should do if you read Zone III instead of Zone V, is it not? (See, I even used the Roman numerals.)
Thanks for the quick responses! I'll just shoot at the recommended levels for now and experiment with different EI to find the look I like when I'm more comfortable.
Generous. You can just about go to 3 stops down with the right film/dev combination, even at ISO speed and contrast. I go for 2-1/2 stops down; you go for 2. Which shows how flexble the process is and how we all make our compromises...
Originally Posted by gainer
Pity the Romans never mastered fractions: I love Zonies who use Zone II-1/2...
You mean Zone II.V ?
Originally Posted by Roger Hicks