Gum Bichromate printing is an alternative process that allows you to print as many or few colors as you prefer, using watercolor pigment. Here are a few trial prints and how they look after each color pass. Each pass consists of coating the paper with sensitized pigment solution, drying, contact print exposure under UV light, development, and drying.
Cyan Pass using Cyanotype & Yellow Pass
(with Gum Bichromate printing you can use Cyanotype for the Cyan Pass in lieu of a blue pigment)
Magenta and Black Pass
(The Black Pass tends to stay very light. You can build any color up with multiple passes)
Final Cyan Pass with Cyanotype
(In a smaller print the cyanotype responded nicely, these were 3″ x 4″. The cyanotype can have a tendency to bead up on larger surfaces that have a lot of gum built up).
This is a trial print in which I was working with curves and a different method for preparing my digital negatives in attempt to get more detail in the hair and face.
Cyan Pass using Cyanotype
Black Pass (The method I was trying did not work well on this seperation negative. It did not block the highlights and muddied down the print).
Final Cyan Pass (Cyanotype. This is an example on how the Cyanotype may not work well on larger prints. This is around 7″ x 11″ and you can see areas in which the cyanotype beaded up). You will also be able to see that this method compared to the image below, can produce flat flat/dull results. I have not tried to build the colors up with multiple passes … that may be the answer to producing a richer look.
This is the “summertide” print using gum for each layer, including the Cyan pass. The exposure time was a lot higher as well. While I find the rich quality to be absolutely gorgeous, I lose the detail because the pigment layers begin to block up. In the mean time, I’ll continue to work to find a happy medium between the above print and this print.
Here are my beginnings of the experience that IS: Gum Bichromate.
Original Image: B&W Medium Format
Digital Image Design (The texture is a result of how the image was translated after being cropped)
The following images were taken with my cellphone, so pardon the quality.
Tricolor print from one greyscale negative.
Magenta Pass (In the wash — bad light)
Final Pass: Cyan (Blue pigment) I think the pigment mixture was too thick.
I smoothed the layer with a Hake Brush, but it still bubbled. I do, however, love
the rich sepia tone!
“K” Pass – Black
“Y” Pass — Yellow
“C” Pass — Blue
I’m not sure why there is more “Magenta” reading through than the “Cyan” separation (compared to the digital design that I did the CMYK separation negatives). I also think I need to run another “K” pass. I’m thinking either some of it washed away after developing the other passes, or it just looks too weak compared to the other color passes.
All in all though, I feel that these are pretty successful for my first Gum Prints. I also realize that I have to embrace the results — that I cannot totally control the results, but learn from them …