Gum Bichromate

Gum Bichromate is a printing process from the 19th century that was highly regarded as the first colour printing method. any colour can be printed by using layers of different colour pigment and build the image very much like a painting. this therefore gives a huge tonal range and can create very beautiful images . Edward Steichen made one of the most famous gum prints ever and sold for a staggering $2.9 million at auction as shown below


The Pond—Moonlight by Edward Steichen, 1904

the colour tone i used for my first gum print is a umbre tone. first step is to mix your sensitised liquid that will be painted onto your surface. i mixed gum arabic which is a by product of sap from an acacia tree. there are a few different versions of gums you can use powdered gum arabic or the ready mixed liquid. it is also possible to use Poly Vinyl Acetate as gum. you then proceed to mix in my dichromate.  once this is dry it becomes light sensitive so its very important to be ready to leave it to dry in a light tight environment. i painted the gum on the photographic surface which in this instance is alkaline based watercolor paper

*just a sidenote for anyone trying this at home you have to take great care when mixing your dichromate to your gum arabic as dichromate is a known carcinogen.

the image i chose to attempt on gum was of a sculpture in coventry at the war memorial. as shown below


the first step was to invert the image in photoshop and print onto acetate as shown below


you now have all your elements to make a gum bichromate print the next step is to put them together and expose. the ready dried gum watercolor surface goes first and then overlay the acetate sheet and then clip the glass over the top this maintains a tight press of acetate to paper. then leave out in the sun for around 15 minutes. this then develops the now uv sensitive paper.

IMG_4999 2

once the image was done i moved back to the darkroom and rinsed in moving water but not direct impact for about 10 minutes to fix the image.


this is the final fixed gum bichromate print i am not overly happy with the final result allthough for a first try one cannot complain. i will most definately be doing this again maybe some multiple layers of different tones to build some RGB.

until next time

PJ x


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