Sustainable Plant Proteins as a Less-toxic Alternative to the Gum-bichromate Process
Lupin
I started using the Chiba system in 2010 as a less toxic alternative to gum-bichromate printing; firstly with pork gelatine, then casein and later, fish gelatine. After 2013, I explored other alt-processes: cyanotype, argyrotype, solargraphy, and cuprotype. In 2023, I started to think about the Chiba approach with the use of plant proteins in alt-pigment printing process. Today, I continue to research plant protein alternatives and other greener processes such as zerochrome-SbQ. Later in 2026, I look forward to publishing more findings on plant protein-based printing using wheat, soy and other proteins.
I published an article on Alternativephotography.com in 2024, detailing the use of lupin protein in Chiba-based printing. You can download an updated version here: 2026 UPDATE–LUPIN-Sustainable Plant Proteins
Wheat, Soy, Yellow pea…
Following my initial investigations into more soluble plant proteins (lupin, plant protein albumins) in 2023, for use in pigment-based printing (gum-bichromate), I considered the possibility of increasing the solubility of proteins that are poorly soluble in water. Most storage (seed) plant proteins fall into this category, for if they did not, the proteins would wash out of the seeds in the rain or when sitting on the wet ground (nature by design). Without considering modification, it would leave the bulk of proteins out of reach for this application.
In researching gelatine production, it became known to me that collagen protein is also poorly soluble, and therefore must be chemically treated. In essence, the process requires very specific conditions to allow the protein to be extracted and maintain the unique property of going from a gel state to a liquid state above room temperature. If over processed, the gelatine will not gel, which would greatly limit its use where gels are a convenient state, especially in photographic emulsions. In working with plant proteins, there are also narrow bands where processing is optimal for different applications such as photo-sensitized coatings for printing etc…