RE: Colour of Van Dyke Prints...

The color of a VDB print will intensity
significantly in fixer, and also on dry down.

If you don't have any sodium thiosulfate try
your normal paper fixer at about 1/2 normal
strength.

Also remember that for reasonable stability VDB
prints need to be toned. Fix with gold, platinum
or palladium before fixing, or with selenium
after fixing. Don't use selenium before fixing
because it reacts with any silver nitrate that is
left in the paper as well as the silver metal of
the image. For some toning formulas that work
with VDB see my article on kallitype printing at
http://unblinkingeye.com/Articles/Kallitype/kallitype.html.
The toners and toning norms that we use with
kallitype tend to work also very well with VDB.

One more note. Some parts of the literature on
VDB are seriously flawed. Two examples.

Example 1 -- The literature suggests that you can
change contrast by the use of dichromate (as we
do with kallitype based on ferric oxalate),
either by adding the dichromate to the developer
or to the sensitizing solution. Doing so will
change speed but not contrast. This does not
work. The addition of dichromate results in a
loss of sensitivity but does nothing to change
contrast.

Example 2 -- Most sources recommend a first
wash/developing in a running water-bath for 1-2
minutes. This is fine if the water is base or
slightly acidic, but disastrous if the water is
alkaline because in that case the residual ferric
salts that were left in the print after
development reactions will be changed to iron
hydroxide, causing staining that is virtually
impossible to remove. Instead of the running
water bath I recommend soaking the print for 2-3
minutes in a bath of water that has been made
acidic by the addition of about 1/2 teaspoonful
of citric acid per liter water. This will clear
virtually all of the ferric salts. Follow this
with a 1-2 minute running bath.

Sandy King

>I´ve no Thiosulfate here right now.
>Is it possible to take a paper/film fixer with Thiosulfate including
>Thanks
>Christina
>
>
>From: Christina [mailto:darvida@gmx.at]
>Sent: Sonntag, 14. November 2004 09:42
>To: alt-photo-process-l@sask.usask.ca
>Subject: Colour of Van Dyke Prints...
>
>Yesterday I was making some Van Dyke Prints
>using the formula from Worobiec/Spence:
>
>Solution A: Ferric ammonium citrate 6g + 22ml water
>Solution B: Silver nitrate 2,5g + 22ml water
>Solution C: Tartaric acid 1g + 22ml water
>I use destilled water for mixing it.
>
>One part A + one part C mixed together an then
>one part B drop per drop mixed to the solution.
>
>For exposure I use a 8 UVA- 8W lamps with about 25cm away from the paper.
>Exposure time was about 5-7 minutes.
>
>Developing was in clear water (roomtemperature).
>
>All my prints are light brown to orangeŠ.no the blackbrown I was expecting.
>How can I get those black brown prints, like they are shown in the book.
>More exposure?
>Other Formula?
>Developing in warm water?
>I did not fix the prints, will I get a darker brown if fixed?
>
>Thanks very much for your help,
>Lg
>Christina
Received on Sun Nov 14 09:23:52 2004