Re: rodinal developer for infrared

[Murray White <murphy@xxxxxxxxxxxxx>]

Dr. Robert A. Cassanova At 07:21 PM 9/12/96 +0100, you wrote:
>My experience with the Konica IR is as follows:     I meter with an
>incident meter using ASA25 with NO filter in front of the meter.  I use a
>#15 filter and open up 2 stops from the incident meter reading.   I develop
>in D76 per the instructions with the film.     I've also observed that
>opening up 3 stops with #25 is too much.    I don't use the #25 much but
>would guess that opening up 2 stops from an incident measurement at ASA25
>would be about right. 

        Bob--this is the same as others have said but they start at ISO 50.
You have already opened up 1 stop by using ISO 25. Now they also seem to use
a reflected light meter (TTL) and so therefore are in effect using an ISO of
100 if they had used an incident meter unless the meter is measuring from a
gray card.

        From all the posts I have read over the last couple of weeks and
thanks to all, I have this conclusion.

        Using an incident meter
        ISO 100
        #25 or even #29 filter
        compensate by 2 stops of increased exposure or simply set the meter
to ISO 25 and use that exposure with the filter in front of the lens of the
camera.
        develop D76 full strength 20C for 6 min.

Advise me if I have made some error here.
Murray White APPO MPA
murphy@xxxxxxxxxxxxx
wedding photographer/knife collector


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Topic No. 17