Phenol, Sodium Ascorbate


Made in

Biodegradable 233 Circular 218 Plant-based 169 Recycled 123 Vegan 88 Sodium carbonate 2 Vinegar 15 Water 30

Phenol, Sodium Ascorbate

Eco Doka - Sustainable Darkroom Techniques

This project investigates the toxic nature of analogue photographic processes and the sustainable alternatives that are available. Due to the mishandling of special and toxic waste, a significant amount of territory in the south of Italy and numerous countries in the African continent are severely polluted. The levels of toxicity in the land and air affect the local communities with diseases and disrupt the quality of locally grown produce. Analogue photography plays a part in the pollution of the territories in which it is operated, creating the need for a sustainable alternative.
The photographic method comprises three chemical processes - development, stop, fixing - which utilise harmful substances to this day, to which very few alternatives are available in the market and none are able to replace the process in its entirety in an eco-friendly way.
Studies demonstrate that ascorbic acid (vitamin C) has the ability to reduce silver ions, proving its action as a developing agent, first patented by Heinz Ohle in 1932. Ascorbic acid, like hydroquinone - the substance found in commercially available film and paper developers, acts more strongly at higher solution alkalinities giving images with a low fogging result. Sodium carbonate/bicarbonate (soda) works as a pH adjusting agent in combination with ascorbic acid bonding in sodium ascorbate.
Working in conjunction with sodium, ascorbate is a polyphenolic compound extracted naturally from a variety of sources, from fungi to the plant kingdom.
Phenol extraction may involve water and/or ethanol, depending on the polarity of the source. Alcohol used in fresh plant preparations dehydrates the plant cells, pulling all the constituents out of the plant and into solution.
The resulting developer mixture works in reducing silver halides on black and white film and paper and produces high quality images as well as its commercial adversary.
The second part of the process - stop - acts as an intermediate chemical bath to halt the action of the developer and offer a cross contamination barrier with the following fixer bath. A highly acidic solution is necessary to perform as a stop, and the simplest alternative to the market counterpart is a mixture of water/rain water and acidic elements such as vinegar, citric acid or lemon juice (1-9).
The fixer stabilises the image, removing the unexposed silver halide remaining on the photographic film or photographic paper, rendering it no longer photo-sensitive. The prime ingredient of the fixing solution is ammonium thiosulfate, which is not classified as environmentally hazardous, however this does not eliminate the possibility that excessive or large spills can have harmful or damaging effects on the environment. Additionally, it is classified as a HDP - Hazardous Decomposition Products: Heating this product will evolve ammonia. Ammonia (16-25%) may form flammable mixtures in air. Heating to dryness will cause production of ammonia, oxides of sulphur, ammonium sulfate and its compounds are discharged into the receiving body of water, it endangers fish life, even at a relatively low concentration. The most known eco-friendly substitute is the salt fixer, a highly saturated salt water solution. Its action is however extremely slow and potentially inefficient in the long term. The artist collaborates with chemists to find ways to boost the action of the salt fixer adding MSM (methyl sulfone) which has many claims of benefits in healthcare and beauty products as a sulphur supplement for diet, it is naturally sourced in garlic, onions, legumes, cruciferous veggies. Adding other salts such as potassium bromide can also accelerate the action of the salt fixer and, when used in developers in small quantities, may act as a fog restrainer due to its ability to differentiate between exposed and unexposed crystals of silver halide.

Additional information

The techniques used depend on polyphenolic and sodium ascorbate base with a circular component in mind. Plant-based elements allow for an environmentally safe mixture that matches the results of commercially available chemicals without the use of oil refining by-products and benzene derivatives. The prime ingredients of the chemicals can be found in nature and extracted with natural solvents of opposite polarity through boiling and maceration methods, creating a solution that is safe to use and to discard. The waste products can be recycled into compost or fast biodegradable matter.

Information submitted by the maker and edited by the Future Materials Bank.


Ascorbic scid (vitamin C)
sodium carbonate (wash soda)
fruit and plant extract
rain water


Rijksakademie van Beeldende Kunsten