Rollei IR400 reciprocity failure data

roncromberge

Member
Registered User
Hello,

Got my film. 120 and 4x5 sheet. But nowhere find some reciprocity data. [emoji19]

Anyone have some directions, hints, to tackle this film?

Because with a effective EI off 3-6 the chance is real to get shutter times beyond the 2 seconds.

Ron.


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Ian Grant

Well-Known Member
Registered User
How do you get an effective speed of EI 3-6. The manufacturers say it's real speed is 25/15º in IR use with a Kodak Wratten 88a filter, that's not far different to a Hoya R72.

Watch that there's no red indicator lights in the darkroom when loading & unloading film an when loading your developer tank as the IR film's much more sensitive to them.

As they say Reciprocity data is unavailable try using the Ilford SFX curve, I added it here in the resources section in the discussion of Ilford Reciprocity.

Ian
 

Kevin Allan

New Member
Registered User
ISO 6 is what I generally use with Rollei IR400 and a Hoya R72 filter. In bright sunlight I rarely need to use a shutter speed longer than 1s so haven't made any reciprocity adjustments.
 

mpirie

Active Member
Registered User
Likewise, i use an effective speed of EI 3 with an R72......i like a robust negative.

If we lose two-thirds of a stop for processing corrections, then 320 less the R72's 6 stops makes it EI 5.

If you leave it at ISO 400, then the 6 stop reduction will take you down to EI 6.

Good enough for a ball-park exposure.

Mike
 

Ian Grant

Well-Known Member
Registered User
I suspect the EI of 6 is due to reciprocity failure, an R72 filter has a filter factor of 16 which is 4 stops not 6.

Ian
 

roncromberge

Member
Registered User
Thanks for all your useful data.

You will see the results hopefully soon [emoji4]


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Darren Lewey

Member
Registered User
I worked with the Rollei film + R72 filter, the back end of last year. I set the ISO at 6 and typically found exposures metered at around 1/2 - 2 seconds, spot metering for the darkest parts. With a 1 second, I would expose for 2 seconds and 2 seconds, I would expose for 8. I found these on the thin side but were perfectly useable and I didn't make any ongoing adjustments.

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