Re: Merits and Demerits of Salted vs. VDB
Here's an example of 11 VDB prints exposed identically and then
treated in different toners and toner/fix sequences using a 2% citric
acid 1st wash. The actual color of the scans is a bit too yellow but
it shows clearly the relative color and density differences. 10
prints are on ecruwhite Cranes' Kid Finish Stationery and one on the
white flavor of that paper. There is also a comparison between
untoned prints single-vs. double-coated.
The image is a nude in the woods so be forewarned:
http://my.net-link.net/~jsmigiel/images/technical/toners/
vdb_test_11.28.05.jpg
I would not recommend selenium toning (KRST= Kodak Rapid Selenium
Toner in the description) for VDB because of the bleaching effect
even at a dilution of 1+500. Selenium-sulphide toners such as
Polytoner both bleach and fog VDBs depending on the tone/fix sequence
as shown in the example.
The use of a gold-thiourea toner (e.g., Clerc's formula) imparts a
very nice purplish tone if extended long enough with both VDB and
salted paper processes. I think it looks sweet with an ecru paper.
Joe
On Sep 1, 2007, at 11:16 AM, Christina Z. Anderson wrote:
Ross,
I think the public would be hard pressed to tell the difference
between the two in a finished print but salt has traditionally been
called the poor man's platinum because of its very long tonal
range. On Weston paper the VDB and salt look very similar tonally,
to me, with about the same amount of stops, but generally you have
to use a flatter neg with VDB than with salt. If you match the neg
to each process with a digital curve and digital negatives, I think
it would be hard to tell the difference even more.
There are 6 processes I teach in my alt class--first cyanotype to
learn the digineg process, then we move to VDB and argyrotype, then
gum, then pt/pd and then salt. This past year I eliminated
argyrotype and made salt optional though I demoed it, because all
three are essentially brownprint processes and it wasn't really
necessary to have them do all three.
However, in my packet of step wedges and test prints and tonal
palettes printed in both, I notice that there is a fading and
yellowing and mottling in the VDB packet I do not see in salt. The
salt prints look exactly like they did the day I made them. In the
troubleshooting section of my VDB chapter (Alt Proc Condensed) I
have a quote from Mike Ware via Wynn White: "Most sources state
that Vandyke prints can be cleared in plain water. In Mike Ware's
description of the argyrotype process he explains the problems iron-
based silver processes have. If processed in an alkaline solution
residual ferric iron is left in the print which will eventually
cause it to fade since iron (III) will oxidize silver."
With test strips and wedges since I am only using them to scan and
read data, I am not as careful in my washing/fixing. Thus these
WOULD be more prone to showing incorrect processing, which they
do. BUT, where VDB uses iron in the mix, salt does not--salt is a
silver/chloride process and VDB is a silver/iron process in other
words. Hence, this could be one reason to prefer salt. If you are
careful with your processing and use citric acid in your wash baths
for VDB so the pH is below 7, Ware says this should solve that
problem.
If a salt print looks gross as Sandy says it is a fogging that
occurs immediately. This is due (if there is no undue light
exposure) to a paper without enough sizing so that the solution
sinks too far into the paper. Buxton, a great paper for cyanotype,
looked terrible with salt when I used it. BUT the other thing not
enough sizing does is not provide enough organic compounds in
excess for the whole process to occur. If organics are not in
excess proportion to the silver you get a dull grey print. The
active organic substances in some way facilitate the reduction of
silver chloride. Ryuji could explain why this is so, I have no idea.
One more thing you can do with salt--vary the color of the print
from sepia to red brown depending on your salt form--ammonium
chloride is more red brown. You can tone both processes.
VDB is such a quick, easy process, not requiring the two step size
and then sensitize that salt does. But if I were to choose one
over the other I would choose salt. But in a classroom, VDB is way
easier to teach and students tend to be more successful with it.
This is obviously way more than you need to know but you asked...
Chris
From: "Ross Chambers" <maelduin@ozemail.com.au>
To: <alt-photo-process-l@usask.ca>
Sent: Saturday, September 01, 2007 2:06 AM
Subject: Merits and Demerits of Salted vs. VDB
To the brown folk,
I've made my first VDB prints today.
I've had a few sessions with salted prints, with which I was
fairly happy.
The VDB prints were, to my eye, not remarkably different (same
paper, same
exposure conditions: the Sun), although I did lose a couple when
following a
prescribed selenium toning step (fade to white!)
So, re the header, do experienced practioners of these techniques
find
greater merits in one or the other? Do the contrast ranges of the
negative
favour one or the other?
Regards - Ross
===========================
Ross Chambers
Blue Mountains
New South Wales
Australia
maelduin@ozemail.com.au
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