Adam Kimball (akimball@finebrand.com)
Mon, 18 Jan 1999 19:53:41 -0800
Thanks William for you the note-
Well, first off, that email was merely a hypothesis- and like any hypothesis is
quite possibly totally wrong- I thought I'd through it out there for what it is
worth... if anything.
My point was merely that if you are looking for the ultimate single-coat print, a
good place to tighten things down would be the amount of metal and iron that
actually gets on the paper. When I rod coat, I routinely end up with sensitizer
that I push right off the paper at the end. The paper (mainly Platine) simply
doesn't take as much emulsion as I'd like to put on it. Now, maybe the addition of
some water doesn't affect this - maybe the paper fibers will take on extra water
after it has stopped taking on sensitizer? I have no idea. However, if it isn't
the case, I think my point has some some validity (a drop at least?) - get more
metal and iron onto the paper, and get deeper blacks. So, if you use a highly
saturated ferric oxalate, a saturated metal salt solution - with as little water
present as possible, you might get deeper blacks. I don't brush coat at all, so I
speak only from rod coating experience...
Eric Nielsen - you out there? Any opinion on the matter? I know you've spent some
time thinking about saturation. Rudiak - anything? Weese, Sullivan, where are the
platinum printers - counting drops?
I'd personally love to learn more about this..
-Adam
William Laven wrote:
> >Every time you add extra water into the emulsion you are effectively lowering
> >the amount of metal per sqare inch that actually stays on the paper. Using
> >more sensitizer doesn't work - because the paper only takes so much
> >(especially rod coated papers). So, if you can absolutely limit the amount of
> >water by using very saturated metals and iron you theoretically achieve a
> >coating with a richer emulsion, and ideally you get better blacks because of
> >it.
>
> I don't follow the logic of this. Unless one adds copious amounts of water
> to the sensitizer which results in much of the sensitizer not soaking into
> the paper and being "dried away" then the amount of metal per square inch
> is identical without water or wit a little.
>
> I commonly double coat on Arches Platine: 6 drops FeOx Sol.A, 5 drops metal
> for each coat on a 4x5. I use dichromate in the devleoper for contrast
> control. In an experiment to see if I could duplicate the results of double
> coating (higher dmax most notably) with less sensitizer I made a mix of 9
> drops of FeOx Sol. A and 8 drops of metal and 5 drops of water which I then
> split into two portions which were used for double coating. The idea was to
> have one and a half times the amount of sensitizer normally used for single
> coats with the water added to make coating easier. That method results in a
> print superior to a single coat and just a teeny tad weaker than a double
> coat as I normally did it with double the amount of sensitizer. If there
> were significantly less metal per square inchg as you claim, my 1 1/2
> sensitizer-double-coat would have been much weaker. As long as the
> sensitizer gets into the paper -- with whatever amount of water added to it
> -- the same amount of metal is there.
>
> *************************************************************************
> WILLIAM LAVEN PHOTOGRAPHY
>
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>
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