Arc Light

Our assignment in class was to produce a portfolio of images using gum bichromate. It required two elaborate steps to render an image.

First a color image was separated into three black and white images representing green, yellow, and blue. Mind you that each color separation had to be exposed and developed as to keep the color balance. The three separations would later be reassemble using register pins to keep the printing exposure aligned.

The next step was to hand mix the emulsion and spread it on cotton rag paper. I drove from southern Illinois to St. Louis, Missouri to pick up the chemicals from a formulary so that I could complete the assignment on time. (This was long before the internet.)

After the emulsion dried on the paper you would register each of the color separations on the pins and expose it to an arc light, the same level as a welder's torch. The emulsion was hugely insensitive and exposures would be 15 - 20 minutes in broad daylight.

I'm reminded of those blue images I made while looking at these red gladiolus rendered on my iPhone app.