From: Christina Z. Anderson (zphoto@montana.net)
Date: 07/22/03-02:14:43 PM Z
Hi Ed and everyone!!! Miss yououuuuu!
Thanks, Ed, for such clear notes.
The best part of APIS to me is meeting the people there face to face. I
have pictures of some of us that I will try to get to Ed ASAP to have him
put on his website. If you want any hot gossip, you have to email me off
list :) Just kidding.
My personal favorite talk was on soft focus lenses by Russ Young. What an
eloquent speaker he is--too bad he was cut short. His research (his PHD
thesis) on soft focus is phenomenal, even pointing out which of our Icons
including Ansel himself used soft focus.
<Ed said>Gum: For a typical 8x10 print he uses 10 ml of 14 BAUME gum arabic
and 2 g ammonium dichromate.
This I found interesting: that he uses dry dichromate. This was done in
former times, too, and included in that weird patent I posted before APIS. A
must-try.
<Ed said>He also adds one drop of Raphael's Miracle
Muck per 2 ml gum (in this case 5 drops) to eliminate flaking.
For some reason, my proportions are different: I have 1 drop per 1 ml of
gum; am I wrong here?
As for Miracle Muck, from the web:
"Miracle MuckŪ is a water-soluble, non-yellowing, low-acid vinyl
acetate-ethylene (EVA) copolymer emulsion binding agent that is heat
re-activatable. Once applied to a non-metallic surface, it becomes a tough,
permanently flexible polymer film capable of creating a superior bond
between two surfaces. It is often used to join wood to wood, fabric to
wood, fabric to foam core, fabric to gator board, and fabric to mat board.
Because of its ideal properties (i.e. being a low-acid, heat re-activatable
EVA glue), it is used by many conservators in the restoration of old works
of art. Miracle MuckŪ has a very long shelf life in typical indoor
conditions. Care should be taken not to allow Miracle MuckŪ to reach
temperatures above 130 degrees Fahrenheit because this will cause it to
return to its liquid state (the heat re-activatable properties). Also,
freezing will cause it to spoil. For this reason, we cannot ship the
product during certain times of the year to areas of the country which may
be experiencing temperatures consistently below freezing."
<Ed said>Coating: Stuart coats gum with a 6 inch foam paint roller. He
stated that foam rollers are widely reported to not work with gum.
I was sitting in the audience with Brett Borup and his wife, Kim, and funny,
he told me he used a mini roller, too, the day before Stuart's talk. I had
come across it in other books, but the idea never stuck in my mind to try it
until Brett, and then Stuart, showed it did provide even coats. I'm a
believer.
The thing I find most fascinating is what Howard Efner told me that finally
clears up the dichromate speed issue (the chit chat at APIS is what I find
so incredible--all kinds of stuff comes out): that (oh gosh, Howard,
PLEEEEEASE explain this better and more correctly than I will!!!) the
molecular weight of the three dichromates is different. Potassium is the
heaviest, then sodium and then ammonium. This in effect makes the ammonium
provide more dichromate ions to react with the gum and harden it, so it is
not just a question of comparing dilution to dilution,as Sandy King had so
carefully pointed out with his carbon testing. Ammonium at any given equal
concentration will be faster than potassium, as Sandy said. Now, I know
inquiring minds DON'T want to know this, but I find it interesting.
The other thing I found wonderful is that of all people, William Crawford,
author of *Keepers of Light*, was there. I almost got enough nerve to touch
his cloak. He's not dead--and he's actually young! Seriously, though, in
his chapter on gum (which I went back and read) has a little section, pp.
203-204, "Ammonium dichromate gives greater sensitivity for the same
concentration than potassium dichromate does. The speed depends on the
solubility of the dichromate (in other words, on the number of dichromate
ions that can be put into solution)and on the pH of the resulting solution.
(Printing speed decreases as the pH goes up--increased alkalinity changes
the dichromate into the much less sensitive monochromate)."
I've seen the Light--and the author of it.
Chris
PS Don Bryant, was this post in keeping with your saying I talk too much? :)
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