Technique
What is Gum Bichromate?
Gum bichromate printing is a nineteenth‑century photographic process where pigment, light, and water build images in delicate layers.
Materials and variables
- Watercolor pigment + gum arabic + dichromate sensitizer
- Paper preparation (sizing, humidity, pre‑shrink)
- UV light exposure and wash timing
- Layer registration (alignment, pressure, drying)
Workflow (high level)
- Prepare and size the paper, then sensitize the first layer.
- Expose under UV and develop in water.
- Dry the sheet and register the next layer.
- Repeat for tricolor gum bichromate (CMYK or RGB layers).
Why I return to it
Gum bichromate gives me a tactile, painterly image while keeping the photographic origin.
It is slow, physical, and unrepeatable — the qualities I want to preserve in the finished work.
FAQ
What is gum bichromate?
Gum bichromate is a nineteenth‑century photographic process where pigment is sensitized to light and built in layers on paper.
What does tricolor gum bichromate mean?
Tricolor gum bichromate uses multiple color layers (often CMYK or RGB) to build a full‑color print through separate exposures.
Is color gum bichromate different?
Color gum bichromate refers to working with several pigment layers; each pass is registered by hand, so every print is unique.