Reciprocity failure

[Pfiltz]

This shot was posted on this forum, the photographer listed

Fomapan 100
R09 1+50 for 8 minutes.

Thread was http://www.largeformatphotography.in...s-Edge/page229

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So with film loosing it's sensitivity, after around 1 second exposure, how do you shoot an 8 minute exposure.

So, for example, a 10 second metered exposure will need approx. 100 seconds. A 4 second might need 8, how does one shoot 8 minutes...?

Was that 8 minutes something quite shorter originally, but then time was added because of Reciprocity Failure playing a influence on the shot?

[E. von Hoegh]

8 minutes is the time the film was in the developer.

[Pfiltz]

8 minutes is the time the film was in the developer.

OH

So I should be able to find some chart for my film, like Arista 100, and see what I should develope an image for, base on it's exposure time, especially if it was exposed for 1 second or longer?

I'll see if I can find that. I'm not sure I'll be developing my 4x5 on a routine bases, but do plan an attempt too when it comes in, just to test to see if I can. I have some "Ecopro to make XTOL, and some Arista Stop Bath coming in, along with my film.

I think I found something that I can use, if need be.

http://home.earthlink.net/~kitathome...eciprocity.htm

and

I did read this which was suggested here on the forum

http://filmphotographyproject.com/co...rocity-failure

[Heroique]

Let’s say 8 minutes was the final exposure choice (not development time).

Here’s how it might have happened:

First, you meter that scene for 1/15th sec.

You decide you want a really long exposure, so you pull out your 10-stop ND filter.

10 stops is 1000x – so 1/15th sec x 1000 is (about) 1 minute.

Next, you consult your reciprocity chart for a 1 minute exposure – and the chart recommends, say, about 7 or 8 minutes.

Go ahead and shoot the recommendation. Bracket w/ a couple more shots, maybe 6 minutes and 10 minutes. Take plenty of field notes. Head home and develop your film. Take additional notes about your processing. Evaluate your final results. Scan your film and share it here. Tell us your story. Let the experts here astonish you w/ their endless wisdom. Then, head back into the field w/ greater knowledge and improved technique. Come back w/ your next round of shots and astonish the beginners with what you now know. Reassure them that you were once a beginner too, and that practice made you the helpful person you are now.

[mandoman7]

... Scan your film and share it here. Tell us your story. Let the experts here astonish you w/ their endless wisdom. Then, head back into the field w/ greater knowledge and improved technique. Come back w/ your next round of shots and astonish the beginners with what you now know. Reassure them that you were once a beginner too, and that practice made you the helpful person you are now.

Totally! Few seem to appreciate the process of exploring and trying things out with all the answers available now via google. Nothing like making an idiot of yourself first, though, to really make a lesson sink in.

[Helen Bach]

Fortunately the curiosity to understand something and the enjoyment of practical experimentation and exploration are not mutually exclusive, though some people seem to think that they are.

[Pfiltz]

Few seem to appreciate the process of exploring and trying things out

If that was true, I would have never ventured into Film, especially now.

[mandoman7]

If that was true, I would have never ventured into Film, especially now.

My apologies, as what you say is true. And its smarter, really, to research processing info on this forum before trying out tricky procedures as well. Its an old guy's lament I guess, maybe just a rationalization for all the film I've ruined in the past.

[Leigh]

...maybe just a rationalization for all the film I've ruined in the past.

'Tis oft said... "We learn from our mistakes."

That's why I know so much.

The procedure is quite simple:
1) Enumerate all possible ways to do something.
2) Through experimentation, identify all of those that are wrong.
3) The ones left on the list are right.

Voilà!

- Leigh

[cyrus]

One of the interesting things about reciprocity failure is that it is hard to OVER-expose.

Once you're in the area of LONG exposures, a bit longer exposure doesn't really make a difference in the result. So, for example you needed a total of 10 minute exposure (including adjustment for reciprocity failure) you can have a 15 minute exposure and the extra 5 minutes of exposure really won't make a whole heck of a lot of difference in the outcome.

If you look at the H&D curve, you can see why this would be the case: up on the shoulder of the curve, which is the region for the longest exposures, any incremental additional exposure results in only a comparatively small increase in density. And the longer the exposure required, the smaller the effect of exceeding that time limit. So... don't worry about over exposing.