As Judy says that is a lot of gum in the archive.
You may see from this exchange that there many ways of making gum prints; none
of them are wrong, if you get a result, but some are more right than others.
You say *I alwas preshrink the paper. I always size the paper three times. I
don't
use formaldehyde since I started growing these extra ears and fingers...;-)
I use chrome alum as a hardener with the gelatin in one solution. I always
use surgeon's gloves and use a good exhaust fan at all times."
i do not do any of these things and have been getting gum prints good enough for
display in national institutions for over twenty years.
When they are published people come to see me from around the world. Judy does
not believe me.
You say "The paper I use is Rives BFK and the multiple layers of size does not
eliminate it's
tooth." If you use Fabriano 5 or Bockingford you will not need to size for the
first coat. Dichromated Gloy as an undercoat obviates the use of any size at
all. Judy believes I am telling fibs.
Some pigments stain, for example Hookers Green. W & N publish a guide to how the
colours behave. They are far better at mixing colours into media. They have been
doing for a living for two hundred years.
You will get far better results if you measure out the solutions with an old
spoon. I use the same proportions.
I never weigh or measure the pigment. I mix the pigment with the gum on a
white plate until I have the strength I need. That is what painters do. Why do
photographers need to be different.
Appreciable differences in behaviour of the colour usually result from the
amount of pigment that is needed for a given saturation. This results from the
reflectivity of the different colours. Because the make up of colours can vary,
it is sensible to standardise on those of an established manufacturer.
I can see little point in the complicated washing procedure at each development.
My own practice renders the kind of tests you are suggesting unnecessary. But I
can see that they are of academic interest. Are you interested in publishing
them ?
My method is simple and it works well. Gum printing giives greater freedom. Why
make it unnecessarily difficult?
I do not understand what you mean by setting the highlights. Surely it is better
to stick with water-colour as gouache is designed to be opaque and contains far
more pigment which will only make your task harder.
Terry