That's really fascinating that your results are so different from mine. Our
tap water here is extremely alkaline, but I have no idea how much iron is
in there. I do use distilled water for the silver nitrate as well, so that
can't be a factor. I believe at least one source I read said to age the
solution before use, though it did not mention why. My freshly mixed
solution prints deeper (I have not read it with a densitometer, but it is
visually much darker), longer scaled, and cooler than just a few days
later. Older solutions, say a month or so old, work fine but will only give
a weaker and warmer brown.
Does your aged solution give off much precipitation? My friend Bob Routh
says that he is convinced that the solution is not light sensitive, and he
even puts the clear bottle out in bright sun to precipitate whatever silver
that will settle to the bottom, which allows him to filter it out! He's
been printing for decades as well.
Maybe there really are differences between the North and the South, besides
politics and temperature! There must be ways we "hold our mouth right"
during printing sessions that differ as well.
So pray tell how is your casein experience different from mine?
>My experience with the Van Dyke solution runs counter to Sam's. For me,
>freshly mixed solutions print grayer with lower dmax, less contrast and with
>sometimes marked uneveness. As a result I now age the mixed solution at least
>a couple weeks before using it. The problems disappear with the aged solution
>and the printing characteristics just seem to get better as it ripens. (BTW,
>I also print on Cranes' Kid Finish, as well as Platine, and Bienfang 360.)
>Maybe it's the water? I mix the silver nitrate with distilled water, but just
>use tap water for the other two solutions. Lots of iron in the water in
>Kalamazoo. Maybe it helps. Other VDB printers around these parts report
>similar experiences with the aged solutions printing better.
>I'm printing this week with a solution mixed 14 months ago and getting fine
>results without any problems. I've stored the solution in an amber glass
>bottle in a closed cupboard for this time.
>Of course my experience with casein bichromate also runs counter to Sams'.
>Wish I could get a handle on that process as he has. :)