Overexposure / Pull Processing

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At what point does this become a bad thing? As I understand it, pull processing is supposed to increase shadow detail. I rate Plus-X at 64 when I process it in Rodinal, but I think that has more to do with true film speed in that developer than anything else. I rated some at 32 and processed it in HC-110 and didn't much care for the results.

My question is, at what point is pull processing the most beneficial? One stop, 2 stops, 3 stops...what? Is this something that is shown in film data?

I figure most things processed in Rodinal probably take a 1 stop hit in film speed. I'm just trying to get a handle on the theory behind overexposure and pull processing.
Thanks,
Nick

Pull processing has to do with development levels that keep the highlights from blocking up. It's sheer practicality. If by exposing generously for best shadow detail, one finds that "normal" development in the developer you are using results in highlights that won't print on the paper, then you have to "pull" them down the scale for easier printing. Do this with less than normal development; or, in my case, use a forgiving developer like D23 which tends to minimize blocking up of high tones with what Adams called it's "semi-compensating" action.

kodachrome64 said:

... At what point does this become a bad thing? ...

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It depends upon the brightness range of the scene. It all goes back to the idea of shooting for the shadows and develop for the highlights. If you simply expose for lots of detail in the shadows, and don't change development, you'll get a thin flat neg on scenes with little contrast, and heavy difficult negs on scenes with big brightness range. To make printing manageable, you adjust the development to get highlights where you want as well as exposing for the shadows.

So, it's not just to get shadow detail, but to address both ends of the negative density range.

Different films can handle different amounts of under and over exposure, and the corresponding push and pull of development, so no single answer will be accurate if one takes your question absolutely literally.

C

I guess that explains why I didn't get the best results with Plus-X at 32...I was thinking the more exposure the better for shadow detail.

As I understand it, pull processing is supposed to increase shadow detail.

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Pull processing has no real affect on the shadow areas (accept when N-2 or shorter times are used, when mid-tones can suffer from lack of contrast, this is when a compensating developer is beneficial instead of pulling the time too much). It has its benefit in holding back density build-up the highlights. Shadow areas are developed early on in the total development time and then they stop. Highlight areas tend to keep building density in the developer up to a certain point until they stop (i.e., the shoulder of the curve)---the point being that highlights build density for much longer during the development time than do the shadow areas.

My question is, at what point is pull processing the most beneficial? One stop, 2 stops, 3 stops...what?

Click to expand...

Testing will tell you this answer, but I realize that you may not be able to do so by creating curves. I think the answer is that it is most beneficial when it can be used without bringing down the mid-tones too much. If you find that pull processing is creating drab mid-tones, then at that time, it's too much.

Just something to chew on--my test with T-Max 100 and D-76 1:1 showed a loss of film speed of 1/3 stop on the N-2 curve. If it seems ok to do so, then I can increase the exposure to the film by +1/3 stop to help support the mid-tones at N-2.