Pulling long exposures with rodinal 1:100

[RodinalDuchamp]

I am getting ready to begin some testing but have done so much research my head is spinning.

I have calculated reciprocity times, factored in my standard pull (tmax 400 @ 200). I have calculated reciprocity failure rates @ 400 and 200.

Basically here is my situation: my usual development method consists of developing 400 speed film at 200 in rodinal for 60 minutes.

I have done this only with 120 film which is much less prone to reciprocity failure. I am trying to find out if I need to dial back development 10-15% to account for the extra exposure time (0.5 stops for tmax @ 8 seconds) or if I should allow the full 60 minutes to take advantage of localized developer exhaustion and rodinals inherent compensating nature to exhaust fully.

If TLTR: should I reduce development 10-15% if pulling tmax 0.5 stops or allow full 60 minute rodinal souping?

Trying to spare as much film as possible so if anyone has personal experience with this dilemma I would highly appreciate your counsel.

I forgot to add I would like to overexpose and underdevelop as my scenes have very extreme contrast ranges since I am shooting long exposures of architecture at night.

[Doremus Scudder]

I am getting ready to begin some testing but have done so much research my head is spinning.

I have calculated reciprocity times, factored in my standard pull (tmax 400 @ 200). I have calculated reciprocity failure rates @ 400 and 200.

Basically here is my situation: my usual development method consists of developing 400 speed film at 200 in rodinal for 60 minutes.

I have done this only with 120 film which is much less prone to reciprocity failure. I am trying to find out if I need to dial back development 10-15% to account for the extra exposure time (0.5 stops for tmax @ 8 seconds) or if I should allow the full 60 minutes to take advantage of localized developer exhaustion and rodinals inherent compensating nature to exhaust fully.

If TLTR: should I reduce development 10-15% if pulling tmax 0.5 stops or allow full 60 minute rodinal souping?

Trying to spare as much film as possible so if anyone has personal experience with this dilemma I would highly appreciate your counsel.

I forgot to add I would like to overexpose and underdevelop as my scenes have very extreme contrast ranges since I am shooting long exposures of architecture at night.

You're not going to like my answer, but bear with me...

First, "pulling" is merely underdeveloping your film from some kind of "normal." This is often done together with an intentional overexposure of the film to "preserve" shadow detail (usually this "overexposure" isn't one at all, but just a way to compensate for less than adequate metering; for example, average metering of a contrasty scene, which will usually end up underexposing the shadows). If this "pulling" is done to reduce contrast and ensure shadow detail, then it has a valid justification. If not, you are merely underdeveloping your film and the resulting reduction in contrast may not be desirable.

Second, rating your film at a slower E.I. may or may not be justified depending on your camera, metering techniques, etc., etc. That said, overexposing TMY by one stop will normally not get you into any difficulties and may provide a bit of a safety zone against underexposure caused by changing light, metering mistakes and so forth. Many of us give a more generous exposure for just this reason.

But (and now comes the important part), the reciprocity characteristics of the film will not change just because you choose to rate the film differently. If you have reciprocity adjustments that you have worked out for a particular film, they are valid regardless of the over- or underexposure you give the film. It's just that your over- or underexposure will affect... well, the exposure.

Reciprocity failure has to do with how areas of the film that receive little light per unit of time fail to respond in a linear fashion when forming a latent image. That means that there are really no different "reciprocity failure rates" for different E.I.s; the film will behave the same as regards reciprocity. However, if you are overexposing and then figuring in reciprocity failure adjustments, you may be adding to the overexposure and figuring in reciprocity adjustments that you don't even need. In practice, and with a stop of overexposure, this is often either negligible or able to be ignored, since one can just work with a denser negative.

Longer exposures, and especially extremely long exposures with lots of reciprocity failure adjustment, effectively increase contrast, since some areas of the negative get enough light to react linearly (i.e., "normally), but others don't. Since we base the reciprocity failure adjustments on the shadow values, the adjustment we make is not necessary for highlight values, which then end up overexposed on the negative. In this case, we compensate by developing less ("pulling" if you like). Careful workers test to find the correct amount of compensation in development time is needed for a particular amount of reciprocity failure adjustment with a particular film. In lieu of that, most manufacturers give some guidelines for reciprocity failure adjustments for times longer than one second that can often be used to extrapolate starting points for longer times. Adjustments in development are often indicated as well.

Also, one particular size of a particular film will not have different reciprocity characteristics from another. TMY in 135, 120, 4x5 and other sizes is all the same emulsion with the same reciprocity characteristics. 120 film is not "much less prone to reciprocity failure" just because of its size.

Bottom line: First you need to determine if you really need E.I. 200 with TMY to get good shadow detail (and you may, don't get me wrong). In any case, figure your reciprocity adjustments based on the most practical and realistic E.I. for your working methods and stick with that. Second, with TMY, "normal" development of negatives with a lot of reciprocity failure adjustment is not going to increase the contrast nearly as much as with "conventional" emulsions. You may not have to reduce development to compensate for extra contrast at moderate levels of adjustment. My adjustments for TMY don't start with development adjustments until the indicated exposure time (not the adjusted time) is more than two minutes. Even then, I usually find that most scenes needing longer exposures are rather flat and often benefit from the increase in contrast caused by reciprocity failure. In dark canyons, I often use up to 20-minute exposure times and usually only "pull" N-1.

Hope this helps,

Doremus

[RodinalDuchamp]

Thanks. I think I should be OK using N. I'll have to test but at least I have somewhat of an idea for useable results.

[StoneNYC]

Thanks. I think I should be OK using N. I'll have to test but at least I have somewhat of an idea for useable results.

I was a little confused as well by your comment about how you are changing from 120 film to a different size and you thought that the reciprocity would change, so am I right in assuming that what you're really saying is that you're changing the type of film you're using not just the format but because you're changing the format you're also changing the type of film for some reason unknown to us?

[Jac@stafford.net]

I was a little confused as well by your comment about how you are changing from 120 film to a different size and you thought that the reciprocity would change, so am I right in assuming that what you're really saying is that you're changing the type of film you're using not just the format but because you're changing the format you're also changing the type of film for some reason unknown to us?

He might be seeing that T-Max in 120 has different development times than the same film in 135 format, as well as 120 being on a heavier base. Add to that the fact that he might be shooting smaller apertures and longer exposures in 4x5 than 120 (for times of 1 to 100 seconds).

T-Max, to me, is a mean film, but I'm an old Tri-X guy - and Tri-X is the name of two different emulsions, and it has changed over the years. To avoid confusion I quit using T-Max even though I have 60 sheets left.

[Corran]

Don't pull using semi-stand development. Unless you need to after seeing the results of your test (I infrequently do that with Pan F+ and Rodinal in very contrasty situations).