Nontoxic darkroom chemicals
From Silvergrain Research
Contents |
Darkroom Safety
Chemicals vary in their toxicity in a very wide range; even when you handle low-toxicity chemicals, the importance of proper safety precautions shouldn't be overlooked. Adapt an adequate safety protocol and prepare the darkroom with necessary safety tools and equipment, such as aprons, nitrile gloves, gogles, face mask, etc. Good ventilation is also important.
Harmful chemicals that can be removed
Common photographic solutions contain following compounds:
- Hydroquinone: It is a very common developing agent used in most developers. Its acute human toxicity is not established, but its toxicity to laboratory animals and aquatic animals are well known. It is a mutagen. It is specified in many regulatory lists. Hydroquinone can be decomposed in a very dilute solution by aeration.
- Metol: It is a very common developing agent, and it is still used in some developers. Although it's becoming less common, Metol can cause chemical allergy.
- Borates (boric acid, borax, metaborate): Borates are very commonly used in film developers and fixers. They are only mildly toxic to mammals, but they are more toxic to plants.
- EDTA: EDTA is a very common chelator to prevent calcium scum and other problems. However, EDTA is hardly biodegradable and it is not effectively removed by sewer treatment plants.
With proper technology and altnernative agents, they can be replaced with safer chemicals without impairing the image quality or changing the processing procedure at all. My recent darkroom chemicals removed all of the above agents, although they are still commonly used by major manufacturers.
Some of my chemicals are freely available as published formulae. Published formulae include: DS-12 film developer, DS-14 print developer, neutral rapid fixer, and washing aid. Some others are available commercially. My latest formulae are manufactured by an industrial chemical plant, and commercially available from Digitaltruth Photo Ltd. Digitaltruth is working to expand its product range, and film developers are expected in later 2006 or early 2007.
My approaches
All of the four chemicals listed above are traditionally used in photography, because they are very effective, cheap and readily available. However, as the level of chemical safety and environmental concern raised in 1990s, many of these agents were added to regulatory lists. Again, with proper handling and disposal, these agents are rarely problematic. Therefore, major manufacturers tend to continue to use them.
However, there are some reasons why I think it is useful to replace them with safer alternatives. One important improvement in removing those chemicals is to lower the risk of potential hazard in case of accidents.
The first is the reduction of potential risk to the darkroom worker and the environment. For example, when a darkroom user inadvertently splashed some processing chemicals into his clothing, where the chemical soaked into the t-shirt but s/he didn't realize this happened until the end of the day. Another scenario might be that, when waste chemicals are accumulated in a vessel for later disposal. The chemical would enter the environment if the vessel leaked, or when the vessel is damaged during transportation. By removing potentially hazardous chemicals, it may cost extra cents to pay for more expensive ingredients, but the overall peace of mind is greatly enhanced.
Some institutions are becoming increasingly concerned about anything that is "chemical" based, and it is used as an excuse to phase out traditional darkroom and completely replace it with digital imaging. By offering a nontoxic alternative, I hope people can make more sensible decision on imaging technology.
Here are some information on how these chemicals are removed from my formulations:
- Hydroquinone: It is replaced with another developing agent closely related to Vitamin C. It is already a safe compound, and it is further decomposed readily by sunlight, microorganisms, and air.
- Metol: It is replaced with Dimezone S, which is used in much smaller quantity and does not cause allergy, even among people who have severe allergy to Metol.
- Borates: They are replaced with other buffering agents. Alternatives include: alkanolamines and carbonates, which are very commonly used in skin care products, body soap, shampoos, and laundry detergents.
- EDTA: It is replaced with a combination of various other compounds. Industrial standard is NTA (nitrilotriacetic acid) or polyphosphates (Calgon, sodium tripolyphosphates, etc.) but many Silvergrain products use a mixture of nontoxic ingredients, such as citric acid, salicylic acid and alkanolamine derivatives.
Why major manufacturers don't offer similar options
Major manufacturers no longer actively develop traditional darkroom chemicals, and therefore they are not very likely to come up with hazard-free products. Even if they had an active product development program, they would have to invest a lot of money on research and development, and manufacturing would cost extra money due to higher cost of safer ingredients.
Major companies probably would pursue the low-toxicity products if the wet-processed traditional photography did not give its way to digital imaging. Shrinking market is a major discouragement to them. Indeed, major companies such as Eastman Kodak, Fujifilm and Ilford spent a great amount of effort during 1990s to replace hydroquinone with Vitamin C, and remove other agents from their products. They obtained numerious patents on these technologies, but none of them was reliable enough to use for commercial products without further improvements.
How Silvergrain and Digitaltruth did it
I was more interested in improving image quality at first. Some of my early formulae replaced hydroquinone with ascorbate for this reason alone, and therefore they were not perfect from non-toxicity viewpoint. But as I accumulated experience with nontoxic formulation approach, I realized that I could remove ALL of the above agents and I could make the chemicals even safer. As an individual photographer, I don't care about $0.50 extra material cost, and I had the right knowledge in improving the research and developments started by the giant players, after they moved on to digital imaging business. At first, I developed all these formulae for my own use in my darkroom. At some point I also had a small darkroom set up in my residence, and safety meant a lot to me when I was printing photographs right next to my kitchen and bathroom.
I also rented space for my photography in commercial buildings. Some are in business district, and some were in artist community buildings (lots of studios), all in Boston, MA. A lot of people asked me if photographic chemicals are dangerous. Those management people and artist neighbors care about environment and safety, and some community had rules to use water-base paints and glues rather than those based on organic solvents, and those people were marginal to the idea of having a photographic darkroom down the hallway. Silvergrain chemicals would have helped me if I had them at that time.
When some of the formulae were developed, I started posting them on the internet, including on my website at http://silvergrain.org for everyone to use them freely. These published formulae became popular among darkroom enthusiasts and chemistry hobbists, but it didn't see widespread use among photographic educators, professional labs, and other large scale users, since these chemicals had to be mixed by the end user from raw chemical stocks. This is simply a lot of work for most people.
At some point, people realized that we could make a much larger positive impact to the photographic world by offering these products pre-mixed, just like other products from Kodak and Ilford. Digitaltruth Photo Ltd was enthusiastic and they now manufacture and sell silvergrain brand chemicals.
Other common ingredients
Photographic chemicals commonly contain several other common ingredients. They are not particularly hazardous. However, whenever possible, I prefer to use ingredients with well known toxicological data. I also prefer to use chemicals that are also used as food additives, cosmetic products, skin care products, detergents and other household products. I also prefer to use ingredients that work with the smallest quantity, so that the potential risk is lowered, and the chemical waste is minimized. The exact ingredients and quantity are proprietary for production formulae, but you are encouraged to inspect product MSDS and published formulae to get general idea of what are in photographic chemicals. (Production formulae often use more sophisticated ingredients that are not readily accessible to darkroom hobbists, while publised formulae tend to limit to most common chemicals that are readily available to them.)
