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Ian: what is the physical mechanism that makes grain worse (do you mean larger or of greater density variation?) when the temp shifts after development? I don't understand how for example a slightly warmer or cooler fixer could affect the grain structure.
The problem is micro or surface reticulation of the film caused by the softening of the emulsion by the deveoper followed by temperature shocks in the process cycle, some films suffer more than others. Rodinal's high pH and specifically the hydroxide increase the potential problem.Quote:
Originally Posted by polyglot
The issue has been know about since the late 1920's or early 30's, it became more important with the rise of 35mm photography, I've BJPA article on reducing grain by wet mounting negatives on a glass slide for enlargement, something Ctein was still doingdecades later for the same reason.
In more recent years Kodak have done a lot of research to help minimise micro/surface reticulation. With papers it causes a mottling on the surface particulary noticeable with glossy papers, it'll happen with RC B&W and Colour papers as well as FB B&W, actually steaming removes it. With the advent of Digital minilabs and negative scanners, and also with high end scanning it became a greater issue, so Kodak altered the emulsion hardening to help eliminate the issues with their colour films making them more scanner friendly.
So some films suffer more than others EFKE will be about the worst due to having less hardening, Foma somewhere in between Ilford's films and most of Kodak's, some Fuji B&W emulsions are softer as well. Then it's a combination of softer emulsion, the developers effect on that emulsion and the care taken in the process cycle.
Ian
So it's not actually a silver-grain thing, but a physical texture issue with the emulsion surface?
Hi Ian,
I'd like to thank you! It has been quite a while since someone shed some additional light on the issue of graininess and Rodinal. The phenmenon of microreticulation is something I stumbled upon when viewing at developed film through a microscope. I provides a strange looking, additional plane of focus and may also be visible in a grain focusser.
The influence of the temperature came up some years ago in german forums. Agfa in their Textbook from 1937 - "Das Agfa Laborhandbuch" - recommended a lower temperature for Rodinal (16 C) than for their other developers (18 C, standard room temperature of the time). Several photographers tried this and got very fine grain with Rodinal and films where this previously seemed impossible, e.g. HP5+.
As I take it from what you wrote above, back in the day emulsions were less hardened and swelling may have been more of a problem with a high-pH, therfore, Agfa recommended a low temperature. With modern emulsions choosing a lower process-temperature may prevent micro-reticulation, when temperature control within 1 C can not be guaranteed. And I think under most circumstances it will be a stretch without dedicated precautions taken.
Best
Stefan
Thanks StefanQuote:
Originally Posted by skahde
Last time I wrote a serious thread on this subject it was hijacked and the points lost because peple deliberately misinterpreted what I'd written.
Yes even when I started in photography back in the 60's films emulsions were significantly softer during processing. FP3 and HP3 which I used at school (cheap ex-Government surpus) were softer than FP4 and HP4, which were again softer than the modern versions FP4+ and HP5+.
I knew that many German 35mm workers used Rodinal at 16?C or 18?C but I haven't come across that particular Agfa reference before, I think ironically I may have a copy of the book but then my German is non existant although I can tranlate a formula :D. What's important today is that the Agfa Rodinal from 1964 onwards has a higher pH and excess Hydroxide compared to the pre WWII version so the issues could be worse.
Part of the problem when discussing the issue of micro (surface) reticulation is most people with a good grasp, understanding and experience of processing should never come across it as a serious problem. However it is the reason why some photographers produce constitent high quality negative and prints while others using the same film/developer combinations can't even when the exposure & dev times are correct.
Ian
Grain is basically built into the film. You can screw around with different developers with very little to show for it. So called fine grain developers have high solvent action that kills fine detail.
So quit fooling around. Options are bigger negative or slower film. Bigger neg is best.
TMax 100 is the finest cleanest easily available film. It works well with my scratch mix D76. The more you dilute the developer, the rougher the grain. If you use stock developer, and then use a stop bath, it works more like 1:1 dilution grain wise. SKIP STOP OR WATER RINSE AND GO STRAIGHT INTO FIX. The only downside is you kill the fix faster. Big deal. I never reuse it on important film anyway. I do use an alkaline fix so water or ss is of little value. In fact alkaline developer, acid fix, and alkaline fix seems silly to me.
The biggest surprise is you will get is over expose one stop and cut development 20%. Shortened time in developer seems to have a much bigger effect than changing developers. To compensate for short times, you need more exposure. The reverse, called pushing, does not work nearly as well if at all. You also get a beautiful tone range with lots of shadow detail and the prints are still sharp. I have tri x prints 6.75 x 10 where you have to look really hard to see the grain.
Grain is a characteristic of the film and is not affected, in itself, by the developer. But the developer can affect the appearance of the grain, as noted above. Most films available today have at least reasonably fine grain. Some, like EFKE 25, have extremely fine grain. You usually will not be bothered by the grain with these films regardless of the developer. But the developer does affect the appearance of the grain. A developer like Rodinal and various "acutance" developers emphasizes apparent sharpness and may emphasize whatever grain there is. But with a very fine grain film, the sharpness is what you notice, not the grain. Fine grain developers etch away the edges of the grain and make it less apparent. But they may degrade sharpness just a bit as well. Developers like D-76 and Xtol are compromises that have fine grain characteristics but still produce good sharpness. Also, as noted above, there is no substitute for square inches when it comes to either fine grain or sharpness. A big negative is the easiest way to get both.