Brian Ellis (beellis@gte.net)
Sun, 24 Oct 1999 07:28:30 -0400
Some people seem to have a severe problem with the anti-halation dye when
using tubes or drums,, others don't, even when using the same equipment,
chemicals, etc. This leads one to think that the nature or quality of the
local water supply has something to do with the severity of the problem. As
you point out, the antihalation dye can be removed by the developer so people
who use tanks or trays don't usually see it. With tubes or drums the back of
the film presses against the back of the tube or drum (in varying degrees,
depending on the contstruction of the particular tube, drum, etc. in question)
so that the developer has difficulty getting to it. This tends to leaves the
dye on the film to some extent, to be made invisible (though not necessarily
completely removed) by the fix or, if not completely by the fix, then by the
clearing bath. At least that's my understanding of what is going on. Brian
FotoDave@aol.com wrote:
> In a message dated 10/22/99 3:52:12 PM Pacific Daylight Time,
> wallen@boulder.nist.gov writes:
>
> > Another way of formulating the question would be to ask: what is the
> > mechanism for the decolorization you talk about?
>
> We actually had a discussion on this a while ago. I speculated (and still
> suspect) that it is the sulfite that clears the stain as developer, fixer,
> and hypo clear all works.
>
> But the problem for me was, when I used the Jobo drum without the ribs to
> process Arista lith film, there were stains on the back and some of the
> stains were tough that it did not completely clear after the soak in the
> above. Others might not have that problem, but I did.
>
> Dave S
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