Part 2 of the series of making a 4-color gum print on Fabriano Artistico paper, glued on a sheet of aluminium. This part describes the making of color separation negatives and registering them with the substrate.

An Oklahoman landscape, the original digital image going to be printed in gum. The image has been sharpened a bit, and the color saturation slightly increased.

Printing the four color separation negatives with an Epson 3880.

It is fun to use different kinds of “incorrect” methods for color separation. Here I split the RGB color channels to grayscale images, and inverted them to negatives for printing CMY gum layers, respectively. The fourth channel is black, which is a grayscale channel mix from the RGB image.

A piece of clear film is taped to one end of the negative. This extra length is later used for registering purposes.

Stacking and taping the negatives together on a light table.

Trimming the stack edge.

Punching registering holes to the stack of the four films. The aluminium sheet is punched in the same way.

Putting the substrate and one of the unstacked negatives to the registration pins…

…and drawing with pencil the area to be sensitized.