Gift of Gary Cullen, who said:

"The coloured dichromates were shot with an argon running at all lines but with 488 blocked with a narrow band filter. So only the deep blue lines and green line were being used for the exposure. I experimented with different paints to get the right shades that would shift correctly when processed to achieve the desired final multi-colour effect (dichromate swells when processed). Only a single exposure was needed. We got shades of red, orange, yellow and green like that. We could also shift the final image towards blue and get blues and greens but those images were not as bright as the longer wavelengths."