What is Gumoil?

Gumoil is a photographic printing process that combines the traditional gum bichromate process with oil printing techniques. It was developed by artist Karl Koenig in the 1990s. The process involves several steps:

1. Preparation of the Paper: The paper is coated with a mixture of gum arabic and a environment friendly photosensitive compound. Previously potassium dichromate or ammonium dichromate were used.
2. Exposure: The coated paper is exposed to ultraviolet (UV) light through a positive. The light hardens the gum arabic in proportion to the exposure, creating a relief image.
3. Development: The print is washed to remove the unhardened gum, leaving a faint image on the paper.
4. Oil Printing: The developed image is then painted over with a roller or by hand using oil-based paint/s. The paint adheres to the areas where the gum had washed away.
5. Finishing: Excess paint is wiped or washed away, leaving a final image with contrasty image and a unique texture.

The gumoil process is appreciated for its ability to produce images with a narrow tonal range and a distinctive, painterly quality. It allows for significant artistic control and can result in prints that are unique and highly expressive. The process can be labor-intensive and requires a good understanding of both the chemistry involved and the aesthetic effects desired.