From the Conservator's Bench: Color Etching
"Color etching" was the only description of the print technique mentioned in the catalogue and object file for Mouse by Jack Coughlin (GM 14.856), but Carole Klein, associate curator of art, was sure that the subtle coloration in this print, one of just four color prints in the 2010 exhibit, A Treasury of American Prints from the Gilcrease Collection, had been achieved by a complicated printing method. Klein asked Chief Conservator Victoria Book to examine the print and help identify the process the artist used to create the print.
The first tantalizing clues are visible with the naked eye. The square impression edge appears deeper and less crisp when compared to single plate prints. There is a light beige, orange-peel like texture background to the print that doesn't continue beyond the impression edge; and most impressively, in the lower left curve of the central circle, the darkest brown ink extends slightly beyond the curve of the black foreground.
Under a microscope, additional characteristics are visible: At least seven parallel lines could be distinguished at each of the four impression edges, indicating that plates were aligned and pressed at least that many times. Five distinct "colors" could also be found: black, and four browns, from very light cream to rich ochre tones. Interestingly, two black plates were used: One layer of black was visible beneath the golden tone, probably one of the first image plates that the artist used; and other series of black lines were clearly applied over the brown layer, as one of the final plates. The layering of multiple plates is what gives the finished print an appearance of depth. The depth is real — at the microscopic level.
The artist used a combination of techniques, including etching and aquatint, to create the image. But, the layering of the plates, visible only by close inspection, is what makes this small print an artistic treasure.
If you have questions about artistic techniques or preservation, you can ask Victoria Book Lupia, our chief conservator. Send questions to: GMConservation@utulsa.edu.