<< Pardon me if this has been discussed before, but why is it that we must
stick to MAXIMUM (saturated) dichromate, either ammonium or potassium?
I remember posting about using MINIMUM dichromate to do the job, a couple
of years ago
<< snip >>
Sam, I still remember reading your post about that from the archive.
For me, it is mainly for speed. Since I use Pot. dichr, if I don't use
saturated dichromate, it is slow. Books say that pot. dirchr. saturates at
around 10%, but I found it actually much more although I didn't take note on
the exact number. If I used 10% dichromate, I found the exposure takes long
(about 10-20 minutes), whereas with saturated dichr. I can use about 4-10
minutes.
For me, that's the main reason. I don't see that much difference in terms of
contrast or other characteristics. There might be some differences, but since
I am working on "calibrating" my own gum printing system, whatever the
difference is (are), it can be calibrated with the negative or the printing,
at least that's what I believe.
>> Not that I am necessarily doing it any better, but my method is quite
different from what "the books" suggest: I dilute my gum with water first,
add pigment till I get the colors I want,
This is very interesting! I thought about doing things like this too, but I
haven't done it yet. This is more like watercolorist or painters' approach. I
also do Chinese brush painting. The way I see it is one can train his/her eye
so that s/he can make judgement from the mixture directly. (In painting, I can
mix the ink and judge the darkness and even gradation while it is on the
palette and *know* how it will look when absorbed on sumie paper and then
dried. It seems to me then one should be able to do such a judgement with gum
mix too). But I figure those (including myself at this stage) with less
experience will desire to have some control using fixed formula.
>> THEN add enough dichromate in powder form to the mixture.
How do you determine the amount of dichromate? Do you determine by the volume
of your mix?