Rodinal and High Film Exposure

RedSun · Jan 19, 2015

I'm still new to Rodinal BW film processing. To achieve higher contrast, should I dilute the chemical more and extend the processing time much longer? Also, can I do more agitation than normal?

Also, is Rodinal suitable for expired film? Or I should use the old D-76 chemical?

RedSun · Jan 19, 2015

Sorry, meant to say "high film contrast".

RedSun · Jan 19, 2015

For very old film (I have some sheet film more than 20 years old), contrast is really a problem. I would not say the film is fogged (not fogged, but just old), but films I processed with regular D-76 is really plain. I figure I'll try with more diluted Rodinal and diluted D-76.

Thomas Bertilsson · Jan 19, 2015

RedSun said:
For very old film (I have some sheet film more than 20 years old), contrast is really a problem. I would not say the film is fogged (not fogged, but just old), but films I processed with regular D-76 is really plain. I figure I'll try with more diluted Rodinal and diluted D-76.

Just as Michael says, diluting the Rodinal or diluting the D-76 will in itself not increase contrast. Whether your film is expired or not has nothing to do with it. Just develop longer to increase contrast. No other tricks necessary.
If you are trying to learn how to process film, may I suggest buying some fresh film instead? It's a much more reliable way to learn the dynamics of film developing. Once you are good at it, it makes more sense trying old expired film, which will have lower contrast, and most likely more base fog.

Trask · Jan 19, 2015

Thomas - your response touches on something I was looking at yesterday, when poking around Flickr re: Microdol-X. I came across several people who pushed film in Microdol-X 1:3, in preference to straight Microdol-X. The only reason for using the diluted version that comes to mind is that it could provide more of a compensation effect, on the theory that pushing will increase contrast so using a diluted developer would counteract the push contrast kick. Make any sense to you?

Thomas Bertilsson · Jan 19, 2015

Trask said:
Thomas - your response touches on something I was looking at yesterday, when poking around Flickr re: Microdol-X. I came across several people who pushed film in Microdol-X 1:3, in preference to straight Microdol-X. The only reason for using the diluted version that comes to mind is that it could provide more of a compensation effect, on the theory that pushing will increase contrast so using a diluted developer would counteract the push contrast kick. Make any sense to you?

Compensation is the opposite of increasing contrast. It is lowering contrast. When you dilute the developer a LOT and develop the film for an extremely long time, you actually lift the shadows while compressing the highlights, which is the essence of compensation.

Lots of confusion out there.

To increase contrast you either increase developing time, or keep the time the same while increasing temperature. You can also make a stronger blend with less dilution to increase contrast.
If you dilute the developer more, you will lower contrast, and have to develop the film even longer to increase contrast. It is counter productive in increasing contrast.

Athiril · Jan 19, 2015

If you got expired film that has base fog. Increasing time and exposure can end up reducing contrast heavily and making everything overly dense as your dmax will come to a halt but your dmin will continue to go up pushing them closer together.

Adding benzotriazole works to cut out the fog and you can increase processing time too. Potassium Bromide also works but I find that benzotriazole increases resolution when doing this.. At least with FP4+ with a non-solvent developer and using enough to give up 2 stops of film speed (the increase being rather significant).

Trask · Jan 20, 2015

Thomas Bertilsson said:
Compensation is the opposite of increasing contrast. It is lowering contrast. When you dilute the developer a LOT and develop the film for an extremely long time, you actually lift the shadows while compressing the highlights, which is the essence of compensation.

Lots of confusion out there.

To increase contrast you either increase developing time, or keep the time the same while increasing temperature. You can also make a stronger blend with less dilution to increase contrast.
If you dilute the developer more, you will lower contrast, and have to develop the film even longer to increase contrast. It is counter productive in increasing contrast.

That's exactly what I thought -- hence my confusion about why one would push HP5+ or Tri-X with dilute Microdol-X. It seemed anithetical to the goal.

Rodinal and High Film Exposure

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