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Rollei 400s and ur filter?
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Hi all, I recently picked up a couple of rolls of rollei infrared 400s and a cheap filter from eby, ( couldn’t justify €100+ for a Hoya ) the filter is sensitive from 780- 1600. Basically I couldn’t find any exposure info on the filter itself but went with a guide I found on flicker or somewhere which was set the iso to 6 and bracket. Even though the filter shows an ev reading of 6 stops less than daylight, and setting the ISo to 6 gave My 6 stops I still bracketed copiously, up to a further 6 stops, I developed in ilfosol 3 for 7.30 but ended up with a nearly blank roll, except for 1 frame where I pulled the filter before the exposure was finished, in error I should add :( and a couple of very faint images. So I’m left wondering what the problem is, is the filter ir factor too high for the films sensitivity, did I grossly under develop or something else my tiny mind can’t think of.id appreciate any suggestions before roll number two goes in the camera.
Hi Tom,
Yes the filter is too dark for this film. Ideally you need an R72 or any filter with a cut off of around 695 to 715nm. The Rollei film has sensitivity to around 820nm but is at its most sensitive at 750nm. So you can see your filter has missed this point.
Regards,
PeterYou could try a deep red filter, I have used it mainly with the old kodak IR film and got some good results, you can also experiment with developers ID11, used to work well for smooth tones and Rodinal gave harsh grainy negs, so choose developer based on your subject. IR is that kind of film you develop your own style. Not sure what speed comparisons can be made between the Rollei and Kodak IR. With the Red filter I rated the Kodak at 100 ISO metering the subject before applying the filter.
i think what you need is an R72 filter
from the HOYA website > http://www.hoyafilter.com/hoya/products/specialeffectsfilters/infraredr72rm90/” onclick=”window.open(this.href);return false;
“Used for photography with infrared films. lnfrared film is also sensitive to ultraviolet
rays and the shorter wavelengths of the visible spectrum so it is necessary to filter out all but the infrared rays.
R72 passes only infrared rays above 720nm; RM90 passes only that above 900nm.
Often used in crime detection, medical photography, detection of distribution of vegetation, etc.
In ordinary photography with infrared film or infrared color film, the Y(K2), O(G), R(25A)
and other filters can also be used to change the contrast or color effect.”
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