Vandyke Brown with Citric Acid

I was doing some testing with a new light source and wanted to try
Vandyke Brown with it. However, since I did not have any tartaric
acid on hand to mix up the classic VDB formula I decided to use
citric acid instead. After a few tests I found that the following
formula works very nicely, with Dmax at least as good as the classic
formula.

If interested, mix as follows.

        Solution A
                75 ml distilled water
                10 grams ferric ammonium citrate
                5 grams citric acid
                Distilled water to 100ml

        Solution B
                40 ml distilled water
                6 grams silver nitrate
                Distilled water to 60 ml

When Solutions A and B are completely dissolved, just mix them
together for a stock solution that should be as long-lived as the
classic VDB formula. Sensitize using about 2.5 ml of this solution
per 8X10 sheet of paper.

In using Rising Stonhenge off the shelf with no acid soak I was able
to get a Dmax of 1.45 with this mixture single coating using about
2.5 ml of solution per 8X10 sheet of paper. That is higher than I
have been able to get in the past single coating Stonhenge using
either the regular VDB formula, kallitype or palladium. These
readings are for native kallitye, with no toning.

Printing times to get the first maximum black from a Stouffer Step
Wedge using this light source (the AmerGraph ULF-28 Continuous Wave
Xenon) are about the same as for palladium, i.e. about 100 units
where one unit equals approximately one second. Printing time with my
bank of BLB tubes was about 300 units, where one unit equals
approximately one second.

Sandy
Received on 05/17/06-08:45:47 AM Z