As per "target" dMax, there was posted to this group sometime ago info on
zillions of papers. Someone with a better memory than me could cite it for
you.
I've double coated two different ways. For a long time, I'd coat with one
full amount of sensitizer (determined by print size), let it soak in 5-15
minutes until it had the dull appearance you mention, then I'd go over it
with a hair dryer, then apply a second full strongth coat. The second coat
would get absorbed very quickly; the first coat took 5-7 passes with the
glass rod, the second coat never more than two. It takes some practice to
get it down. After seeing my VISA bill go up (even w/Bostick and Sullivan's
fair prices) I started experimenting. Now, I measure out 1 1/2 of a full
coat and add distilled water to bring the volume up to what two coats would
be. For example, 17 drops of sensitizer coats a 4x5 print (approx half of
it FeOx, the other half metal) so 34 drops would be the toal amount used
for two full-strongth double coats. So now I take 25 drops of sensitizer
and add 9 drops of H20, giving me a total of 34 drops which I then split
into two equal amounts of 17 drops which get applied as if full strength
sensitizer: coat, dry, recoat, dry again. And I've found in early tests
that these two methods yield identical results in terms of tonal scale and
dMax though the second method uses less metal. Trying to skimp on the
sensitizer by adding more water reduces the dMax and scale. And why double
coat at all -- try it and see the longer scale, the better separation,
especially in the lows, and the higher dMax. This method makes humidifying
the paper unnecessary since that step, I believe, simply helps to integrate
the sensitizer into the paper more, something which happens naturally with
a double coat. (Please note that humidifying with Mike Ware's process
yields dramatic differences, but it works on very different chemicals,
too.)
Also, don't worry that the sensitizer looks flat after soaking in for 5
minutes or more. It should and it doesn't mean its soaked in too far. In
fact, the purpose of double coating is to insure that the fibers are
particularly well soaked. Martin Axon and I discussed this once and he said
its just like shampooing twice to get deeper to the roots.
Bill
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