Recipricocity Failure charts

simon ess

simon ess

Just call me Roxanne.
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Does anyone know of reliable, proven charts.

I'm getting mind boggled with googling.

Particularly interested in Tri-X, Delta 400 and Fomapan 100 and 400.

Thanks
 
Thanks guys

kendo1 said:
There's a section in Digitaltruth (if you click on the link 'site map' at top right)

http://www.digitaltruth.com/data/reciprocity.php

http://www.digitaltruth.com/devchart.php?Film=&Developer=ID-11&mdc=Search&TempUnits=C for ID11
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That could be useful in general.

Peter B said:
There's a recent document from Ilford on this regarding their own films. https://www.ilfordphoto.com/wp/wp-content/uploads/2017/06/Reciprocity-Failure-Compensation.pdf
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Aha! I saw that but hadn't spotted how recent it is.

The interweb bangs on about old, incorrect info. Many thanks.

I think I know where my scientific calculator is.
 
I think there may be more/better information on pinhole websites, as that's where a lot of people will be running into reciprocity failure.
 
Excellent.

Thanks some guy. :)

I reckon this thread is turning into quite a good resource.

Thanks everyone.
 
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Another guy called @steveo_mcg also has a low light set of tables for a few films, which he showed to me. I've made them into a different version, which I'll try to post, but not tonight!
 
Right, I've done a litlle spread sheet of info gained so far, but I can't figure out how to post it here.

Can anyone help please?

Oh, I've used Open Office rather than Microsoft Office.
 
simon ess said:
Right, I've done a litlle spread sheet of info gained so far, but I can't figure out how to post it here.

Can anyone help please?

Oh, I've used Open Office rather than Microsoft Office.
Click to expand...

Take a screen shot, Ctrl + PrtSC if on PC (Just to the right of f12) and save as a picture
 
Yeah, that worked well enough. Thanks Ken

Most of the work in this chart was already done by @Kevin Allan

I've added Delta 400 and HP5

Fomapan 400 is the only other one I wanted, but if anyone has any more let's get them added.

Thanks everyone
 
This is one I made earlier, the numbers probably need an update s I put the date in to distinguish...

Low light film.jpeg

General idea is: green, as metered. Amber, up to one stop extra (in time); might get away with metered. Red, more than one stop extra.

I use exposure compensation on the Pentax LX so I don't have to count elephants; it will meter down to EV 1 or less, and keep the shutter open (in aperture priority) until it's got enough light in. So +1 or +2 compensation works for most cases!

EDIT: thanks ti @steveo_mcg and @Kevin Allan for providing some basic data.
 
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Thanks Chris.

There does seem to be some significant differences between the two sets of numbers which is a bit of a puzzle.
 
simon ess said:
Thanks Chris.

There does seem to be some significant differences between the two sets of numbers which is a bit of a puzzle.
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The data sheets and testing? Yeah They're pretty mad. I think Illford got a bit lazy with the their T grain stuff and just used the same formula, it does work and gives a good exposure but its far too much when you're standing in a cold street covering the lens everytime a car comes past.
 
I remember it used to get fairly complicated using long extensions, and small apertures on monorail cameras using slow color reversal film.
You had both inverse square law and reciprocity failure to cope with, and had to use CC filters to correct for the colour changes due to both.
Not only that but every batch of Kodak professional film came with its own batch correction for colour and exposure.

Even in black and white, Reciprocity failure compensation changes with each batch of film. sometime markedly so. it even changes with the maturity of the film.
 
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steveo_mcg said:
The data sheets and testing? Yeah They're pretty mad. I think Illford got a bit lazy with the their T grain stuff and just used the same formula, it does work and gives a good exposure but its far too much when you're standing in a cold street covering the lens everytime a car comes past.
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Thanks Steven.

I guess the time has come for me to just do it and see what happens.
 
I'm never quite sure that I've got this right, but it seems to me that, compared to a normal exposure, the highlights will often be relatively unaffected by reciprocity failure, but shadow areas will be affected a lot more. The result is, much greater contrast.

But unless it's specifically for long exposure effects, ie night shots, it can work very well, so...

simon ess said:
I guess the time has come for me to just do it and see what happens.
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Yes! I was surprised at the results. One thing I learned from my trial of night shots is that a little dampness means a lot more areas will reflect what light there is, making it more interesting. Too much dampness (ie rain) does weird things with streetlights, interacting with aperture shape in odd ways...

Do show us some results. I'm expecting excellence straight away, in keeping with your normal work, Simon!
 
Thanks Chris. You're too kind.

I shall try 1 or 2 per roll until I get confident in the numbers.
 
ChrisR said:
This is one I made earlier, the numbers probably need an update s I put the date in to distinguish...


General idea is: green, as metered. Amber, up to one stop extra (in time); might get away with metered. Red, more than one stop extra.

I use exposure compensation on the Pentax LX so I don't have to count elephants; it will meter down to EV 1 or less, and keep the shutter open (in aperture priority) until it's got enough light in. So +1 or +2 compensation works for most cases!

EDIT: thanks ti @steveo_mcg and @Kevin Allan for providing some basic data.
Click to expand...
Chris, I think the times in your table for FP4+ are the OLD times given by Ilford - you might want to use their NEW times. So for example a 30s metered time would give an actual exposure time of 73s instead of 155s
Kevin
 
Kevin Allan said:
Chris, I think the times in your table for FP4+ are the OLD times given by Ilford - you might want to use their NEW times. So for example a 30s metered time would give an actual exposure time of 73s instead of 155s
Kevin
Click to expand...

Thanks Kevin, yes, that's what I meant by "the numbers probably need an update". Actually, it seems like a constant race checking one set of numbers from site A with another from site B with datasheets from here and datasheets from then! A lot of companies end their datasheets very early, at 30 seconds. One company, can't remember which at this moment, has graphs without labelled axes, just some hieroglyphs, probably a PDF font problem. Does no-one do QA these days?

Anyway, I wondered whether folk found the idea of colour coding helpful at all?
 
simon ess said:
I shall try 1 or 2 per roll until I get confident in the numbers.
Click to expand...

Sounds a good plan. The key thing for me, though, was taking comprehensive scene and exposure notes, as well as quite a lot of bracketing.Having the notes is really helpful when you get the results back! Since note taking is not my normal discipline, I did find it better to take quite a few low light shots in the same session. Now if I take the odd low light shot, I forget to make notes, then I'm stuck learning what works or not. D'oh!
 
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