Re: [Leica] t-max pre-soak?

["Dan Post" <dwpost@email.msn.com>]

Most B&W film, panchromatic in particular, contain 'dyes' that tend to
absorb certain parts of the spectrum. I would suspect that this is the case,
that the dye is washing out before you develope the film. If you use a
'coupling' developer, like p-aminophenol ( as in Rodinal), and you don't
pre-wet, the effluent you dump looks like grape kool-aid; that is because
the 'dye' is coupled in the developer to a visible anilone, water soluble
form. Tri-x in D-76 sometimes has a magenta cast which will wash out
eventually. It is harmless, and since it ( the dye) serves to absorb parts
of the blue spectrum, for which the film is most sensitive in order to allow
absorbion of green and red light, only during exposure, prewetting the film
should have little effect.

dwpost@msn.com
- -----Original Message-----
From: Damian Dlugolecki <damian@europa.com>
To: leica-users@mejac.palo-alto.ca.us <leica-users@mejac.palo-alto.ca.us>
Date: Sunday, January 11, 1998 7:45 PM
Subject: [Leica] t-max pre-soak?


>
>I have been following Duane Birkey's formula for T-max, that is, using
>higher temperature and less time; 24C for 6 min.  I like the results very
>much.  Another thing I have been doing is pre soaking the film in 24C
>water while I prepare the other solutions.  The water I discard is a light
>amber color.  What happens chemically when I pre soak?  Is this a good
>idea?
>Thanks
>Damian
>