|Project by Scott||posted 11-22-2013 07:15 PM||2439 views||14 times favorited||16 comments|
I used the gum printing process to print a photograph onto a pine board. Gum printing is an old photographic process which was first done in the 1840’s, and uses gum arabic and ammonium dichromate as the light sensitive emulsuion. First you print a photo onto a transparency, then spread the emulsion on the substrate, which can be paper, cloth or wood. Finally, you place the transparency onto the emulsion and expose it to the sun for a couple of minutes, then wash it in warm water. In this case, I used one color, but you can expose multiple colors in succession and create realistic color prints.
I also used some old wood to create the frame.
The transparencies are the ‘foils’ that are used on an overhead projector, but you can print onto them from an inkject printer. Called ‘inkjet transparency film’ and available from any office supply.
You can get the chemicals from here (note it is ammonium dichromate NOT potassium dichromate):
Here is where I learned how. Under the basic steps it shows how to do it for a single color. I wouldn’t bother with the advanced section, all that extra work is not necessary.
To do color, you just create color separations in the software (split into RGB red,green,blue channels), then print 3 transparencies, one for each color. Then you use the opposite color with each transparency, so you use cyan or blue with the red one, magenta or red with the green one, and yellow with the blue one. Then just expose red layer, wash it off and dry, expose green, wash/dry, expose blue and wash/dry.
Here is my color gum printing project: http://lumberjocks.com/projects/95595
-- Scott in North Carolina