From: Eric Neilsen (e.neilsen@worldnet.att.net)
Date: 03/03/03-08:04:15 PM Z
Chris, You might try this...
Coat with a 50/50 mixture of ferric to metal. Do another one with a
40/60 and one with a 60/40 mixture. Which one is faster? Grainer? Has
more contrast? You will note that more than slight changes can be seen.
Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
http://e.neilsen.home.att.net
http://ericneilsenphotography.com
-----Original Message-----
From: Christina Z. Anderson [mailto:zphoto@montana.net]
Sent: Monday, March 03, 2003 2:16 PM
To: Alt Photo List
Subject: platinum questions
Hi list,
I'm finally finishing up all my reading on alt I ever wanted to do
in
my lifetime, and platinum is way over my head. When I pt/pd printed 5
yr
ago I just winged it, you know? So I really need your advice, as the
books
are SOOOO different!
Questions (please excuse my lack of expertise):
1. Why do most people use a bit more of the metal salts than the parts
A/B
combination? e.g.44/46 drops Part A+B/Part C instead of 44/44?
2. Why does a line of demarcation occur with developing if you don't
submerge the print in the developer evenly, if it is a develop- to-
completion process?
3. I am getting so screwed up by the different proportions of chemicals
in
the developers and clears. Is it really that variably OK?
And, for instance, you chemists correct my math: if you are using
30g
of EDTA in 750ml of water, that is a 4% solution, correct? So why does
one
book call that an 8% solution? Why does this same book say a 1%
hydrochoric
acid solution is 1/2 oz HCL to 1 qt water--isn't that a 5.55% solution?
If
the HCL is 37%. What am I doing wrong here in my calculations??
Here's what I have so far, please chime in if I've really got my
formulas screwed up:
1 lb potassium oxalate to 1400ml water to get a 35% solution
1 lb sodium acetate to 1400 ml water
1/2 lb ammonium citrate to 1400ml water
1 lb potassium citrate to 1400ml water
1 lb sodium citrate to 1400ml water
Hydrodchloric acid 1% solution for platinum, 0.5% for palladium
27ml of 37% to 1 liter of water
Phosphoric acid in a 2-4% dilution or 24-48 ml in 1000ml water
EDTA : use in a 2-3% solution, 1 Tablespoon per liter.
Citric acid: use in a 5-15% solution, or 4-12 T
TIA for helping me weed thru this, and then I can go back to gum testing
:)
Chris
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