Gum-Silver Process

[Dwane]

Dwane submitted a new resource:

(there was a url link here which no longer exists) - Gum-Silver Process

Gum-silver Process

Adapted from an entry in the Scientific American Cyclopedia of Formulas, 1932

Solution No. 1 : Dissolve 50 grams of gum Arabic powder in 100 mLs of water. Gum Arabic does not dissolve quickly, but it will dissolve, so have the gum sit in the water over night. The next day it should be completely dissolved. If you already have a commercially prepared gum Arabic solution intended for gum printing, I would suggest you start with this and see how it works.

Solution...

(there was a url link here which no longer exists)

 

[Steve Smith]

Does this need UV light exposure or will it work with visible light?


Steve.

 

[Jim Noel]

T here was a period when people did a lot of experimenting with processes. This was especially true during the depression when photographers tried many ways to reduce costs so they could keep working. This is one of many variations on gum bichromate printing from that era. It most likely does need UV to harden the gum or it will wash off the paper.

 

[Dwane]

Steve - yes, you need a UV source of light.

Jim - I see this as being more closely related to salt printing rather than to gum bichromate printing. In both salt printing and gum-silver, the image is formed by the interaction of the light on silver chloride (salt printing) or silver nitrate(gum-silver). In gum bichromate, the light interacts with the gum, hardening it in direct proportion to the amount of light falling on it, which is related to the different densities in the negative. The pigment dissolved in the gum provides the image, but it is the gum that reacts to the light.

 

[tinyfailures]

Do you mix all 3 in the end to produce: 100mL gum arabic + 6mL acetic acid + 10mL silver nitrate 22%? Or are you just coating what you're referring to as Solution #3: 20mL gum arabic + 6mL acetic acid + 10mL silver nitrate 22%?

 

[Dwane]

Do you mix all 3 in the end to produce: 100mL gum arabic + 6mL acetic acid + 10mL silver nitrate 22%? Or are you just coating what you're referring to as Solution #3: 20mL gum arabic + 6mL acetic acid + 10mL silver nitrate 22%?

You take 10 grams of the gum arabic solution and add 6 mLs of glacial acetic acid to it. Set this aside. Then dissolve 2.2 grams of silver nitrate in 10 mLs of distiller water. After the silver nitrate has dissolved, add this to the gum arabic solution you have set aside. You end up with a solution containing 10 grams of gum arabic solution, 6 mLs of glacial acetic acid, 2.2 grams of silver nitrate, and 10 mLs of water, all mixed together. You don't mix everything together at once, since I doubt if you'll get everything into solution. The order of mixing is important.

Hope this helps.

 

[tinyfailures]

Thanks for the clarification. Given what I have access to, I'll experiment with 20 mL gum arabic (I only have it as a mixed liquid), 6mL undiluted stop bath (which is basically vinegar), and the silver, then expose it for about the same time as a Van Dyke.