CuriosoLab

Plant-based developers: a solution driven by ascorbate and modified by plants.

Seven  groups can be identified:

1. Plant-based or Infusion developers, referring to Talbot's galls infusion, work solely with naturally extracted chemical compounds as the developing agent. Some can differentiate between exposed and non-exposed silver halides, while others cannot. They sometimes function similarly to pyrogallol or catechol-based developers, as many plants contain structurally similar phenolic compounds that reduce silver halides.
   Talbot makes a difference between infusion and tincture in his letters. A tincture is a concentrated extraction, while an infusion is a certain volume of the tincture with water added.

2. Hybrid developers are solutions where the user combines a plant extraction derived from plants, flowers, bark, or any natural source rich in reducers (phenols, flavonoids, tannins, etc.) with a synthetic developer agent. The most common is ascorbic acid, as used in Caffenol-C. In these developers, both the plant extraction and the synthetic agent work in conjunction to process silver halides into metallic silver, with the plant extraction playing an active role in the development process.

3. Ascorbate-plant developers are solutions where the bulk of the silver reduction is performed by sodium ascorbate (Vitamin C converted by a sodium salt), while plant extraction plays a secondary role. Though its effect on silver halides is negligible, it can act as a pH modifier, buffer, restrainer, preservative, stain reducer, or color illusion inducer.

4. Upcycled developers (waste developers) are working solutions for the film lab that use waste-derived materials as their base, repurposing discarded substances into functional chemistry. These can include spent coffee grounds, rusty metals, food scraps, plant residues, or other byproducts that would otherwise be discarded. Some upcycled developers work solely with the extracted compounds as the developing agents, while others combine these recovered materials with additional chemicals, such as ascorbic acid or sulfites, to enhance their performance. The key aspect of upcycled developers is their focus on circularity, reducing environmental impact by transforming waste into a valuable photographic resource.

5. Distilled developers are solutions where specific plant compounds are isolated and purified through advanced techniques, such as distillation or solvent extraction, to obtain more concentrated developing agents. These developers focus on specific chemicals, such as quercetin or catechins, and offer more control over the concentration and chemical interactions involved in silver halide conversion. They represent a more refined approach than infusions, offering precision in the development process while remaining plant-based. 

6. Energy-driven developers are solutions that utilize electromechanical power reduction instead of relying on phenolic compounds to donate electrons for silver halide reduction during film processing. These developers apply energy inputs, like Bach solarization, to enhance the chemical reactions in the development process. The reduction of silver halides is driven by electromechanical forces. A clear example of this is seen in solar prints, where an excess of light energy, rather than chemicals, controls both exposure and development, highlighting how energy can directly impact the photographic process.

7. Metal-Assisted Plant Developers. A group of developers where metal ions—either naturally occurring in plant extracts or intentionally added—enhance or catalyze the reduction of silver halides. For example, iron-rich botanicals or copper-infused plant extractions can act synergistically with plant phenols (and ascorbate if added) to improve development efficiency. These developers operate similarly to traditional iron-based processes but remain rooted in plant-derived chemistry.