Gum Printing Questions

I took a gum printing workshop awhile back and learned some basics and made some successful prints. I am now trying to pick up where left off and make some prints on my own. I have been following the procedures according to my class notes and Christopher James book. I made several exposures using my platinum exposure times as a baseline and then successively longer exposure times. With all of the prints all of the gum washed off almost immediately and I am getting no image at all. I suspect that it is a problem with the gum or the sensitizer but I don't want to just start ordering new supplies without at least some idea of what might be wrong.

Any suggestions would be appreciated.

How long were your exposures? Gum will require a good bit more exposure than other alt processes. Bill Barber

What paper are you using? Gum can require a paper that has a certain amount of "tooth".

Can you please provide us some more information?

• What's the formulation of your coating solution?
  
  
  

  • Gum solution amount?
  • Pigment amount?
  • Dichromate solution amount and strength?
• Paper?
• Coating method?
• Environment? (workplace temperature, humidity)
• Drying time?
• Lightsource?
• Development method?

I normally use 5% dichromate solution and my gum exposure times are about half of my palladium exposures. Gum exposures are usually shorter than the other alt processes such as Cyanotype, Vandyke or Pd...

Another possibility for your problem may be a too great concentration of pigment to gum. If you use too much pigment the uv light can't get through.


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As Bill Barber mentioned it could be you did not expose long enough. How dense are your negatives? Negatives for Gum do not need to be as dense as for Platinum.

You might want to do an exposure test. Use a coated piece of paper and different exposures. Cut the paper into two or more pieces and then do a series of different exposures starting with what you had used before. Double that exposure on the next piece of paper and then maybe double that again on a third piece of paper.


I agree with Loris, we need much more info to help you out

Bruce