Gum Bichromate Printing

[alexmuir]

I am trying to prepare Gum Arabic for this process. It is quite difficult to find ready mixed Gum in larger quantities locally, but I can obtain powder. I bought a kilo, and mixed 220g with around 750ml of distilled water. The result, however, is a very dense mixture, completely unlike the liquid you can buy in small bottles. Does anyone have experience of this? Is it simply a case of adding more water until a suitable consistency is reached? I wonder if I should be aiming at something similar to the art shop stuff, or if thicker is better?
Thanks for any guidance.
Alex


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[koraks]

Let it stand for a few days. It tends to get a little thinner and smoother. In the long term it even ferments and gets a bit more runny (and acidic) in my experience.

[bob carnie]

I am trying to prepare Gum Arabic for this process. It is quite difficult to find ready mixed Gum in larger quantities locally, but I can obtain powder. I bought a kilo, and mixed 220g with around 750ml of distilled water. The result, however, is a very dense mixture, completely unlike the liquid you can buy in small bottles. Does anyone have experience of this? Is it simply a case of adding more water until a suitable consistency is reached? I wonder if I should be aiming at something similar to the art shop stuff, or if thicker is better?
Thanks for any guidance.
Alex


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Where are you located I buy in gallons and have a few to get rid of ... 14 baume works well for my prints

[alexmuir]

Thanks for the replies. I’ve left the stuff I mixed standing to see how it looks in a few days. I would like to get the use of the powder I’ve purchased. Perhaps the suggestion I had about the quantity of gum to water was inaccurate.
I’m located in Glasgow, Scotland, Bob. Otherwise I would have been happy to look at buying some of your surplus, but shipping costs would make it very expensive.
Since posting, I’ve spotted one supplier in London selling 500 and 1000ml quantities, which is more like what I need. I’m going to order some of that to see if it is s better bet than the powder.
Alex


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[bob carnie]

Thanks for the replies. I’ve left the stuff I mixed standing to see how it looks in a few days. I would like to get the use of the powder I’ve purchased. Perhaps the suggestion I had about the quantity of gum to water was inaccurate.
I’m located in Glasgow, Scotland, Bob. Otherwise I would have been happy to look at buying some of your surplus, but shipping costs would make it very expensive.
Since posting, I’ve spotted one supplier in London selling 500 and 1000ml quantities, which is more like what I need. I’m going to order some of that to see if it is s better bet than the powder.
Alex


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Ok too far to ship.... get 14 baume.. most big graphic art suppliers will be able to handle this....

[Andrew O'Neill]

There's got to be a good art supplier in Glasgow. I could have sworn I visited one there...

[alexmuir]

There's got to be a good art supplier in Glasgow. I could have sworn I visited one there...

Hi, Andrew.
There are at least two good art shops, but they only stock the small (60-75ml) bottles which are expensive. I found a shop in London that does 500 and 1000ml bottles, so have ordered some. I don’t know to what extent it’s used in quantity by painters. Perhaps they only need a small volume at a time. I doubt there are very many people up here, or in the UK, actually making Gum prints, so the demand is likely to be quite low.
I split the quantity I had mixed from powder tonight, and added an equal volume of water to one half. It has become more liquid now, and more like the consistency I think I need. I’ll be able to gauge that better when the ready mixed stuff arrives
Alex. .


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[bob carnie]

Hi, Andrew.
There are at least two good art shops, but they only stock the small (60-75ml) bottles which are expensive. I found a shop in London that does 500 and 1000ml bottles, so have ordered some. I don’t know to what extent it’s used in quantity by painters. Perhaps they only need a small volume at a time. I doubt there are very many people up here, or in the UK, actually making Gum prints, so the demand is likely to be quite low.
I split the quantity I had mixed from powder tonight, and added an equal volume of water to one half. It has become more liquid now, and more like the consistency I think I need. I’ll be able to gauge that better when the ready mixed stuff arrives
Alex. .


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gum is very much used in the graphic printing industry ... you should have no issue getting 5 litre containers.