Far red and possibly infrared sensitivity of Fomapan films.

alanrockwood · Jan 30, 2018

Hi Folks. In looking at data sheets for Foma films it seems that the far red sensitivity shown in the figures varies, depending on which film (100, 200, or 400), which format, and possibly the date of the datasheet.

Does anyone know the definitive current information?

Thanks.

aleckurgan · Jan 31, 2018

Fomapan 400 and Foma Retropan 320 do have near infrared sensitivity.

Gerald C Koch · Jan 31, 2018

AFAIK the format doesn't matter as the same emulsion is just coated on different stock. Most films have near infrared sensitivity for what it's worth. What is important is how far the sensitivity extends. However you are not going yo see the Wood effect.

Wallendo · Jan 31, 2018

My personal experience is that shooting Fomapan 100 with an R720 filter produces a blank image.

pentaxuser · Jan 31, 2018

This is only anecdotal as I am not a user of Foma films but a regular user who posts often says that Foma film is good at producing clouds in blue skies without a filter. This was the response he made when I asked about the difficulties of producing clouds in blue skies with a Mju II P&S camera where there is no provision for attaching filters.

He may respond to this thread. His judgement is one I would trust.

pentaxuser

alanrockwood · Jan 31, 2018

Here's an example of what I am talking about. These are spectral sensitivity curves for Fomapan 200 Creative cut and pasted from two different versions of the data sheet.

aleckurgan · Feb 1, 2018

Gerald C Koch said:
AFAIK the format doesn't matter as the same emulsion is just coated on different stock. Most films have near infrared sensitivity for what it's worth. What is important is how far the sensitivity extends. However you are not going yo see the Wood effect.

Gerald this is what I usually get when I expose Fomapan 400 through a Hoya R72. Isn't it the Wood effect? Left to right: no IR filter EI400, R72 EI6, R72 EI1.5.

chip j · Feb 1, 2018

Beautiful shot on the right. I'd like to do that! What is a R72? You exposed the film @Iso 1.5??

aleckurgan · Feb 1, 2018

chip j said:
Beautiful shot on the right. I'd like to do that! What is a R72? You exposed the film @Iso 1.5??

That's an infared filter from Hoya. I shot this at EI6 and gave two extra stops to get more shadow details. But that was for FP400 normal development, these days I shoot it at EI6 (with bracketing of course) and develop longer for more contrast.

MattKing · Feb 1, 2018

The EIs referred to reflect compensation for the (very dark) R72 filter.
That filter cuts off most light below 720nm, which is right at the edge of the visible light-infra-red transition of the spectrum.
Filters like that are way easier to use with a RF or TLR than with an SLR

Far red and possibly infrared sensitivity of Fomapan films.

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