Quote Originally Posted by skahde View Post
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.


Thanks Stefan

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 . 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.