Darkroom Digest: How to Make an Eco-Friendly D-76 B&W Film Developer

September 19, 2016  •  9 Comments

In a previous article, I introduced the concept of eco-friendly darkroom chemicals.  One of my favorite developers of all time is Kodak D-76.  Unfortunately, at this time, Freestyle does not offer a commercial-ready version of D-76, so I am taking the next best step and making my own formula and eliminating hydroquinone (carcinogen).  

Freestyle does offer an eco-friendly version of XTOL, which I use for 35mm roll film because I like its sharpness on the smaller roll films. I just don't use roll film that often, but when I do, I will only be using the eco-friendly version of XTOL moving forward.   

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FORMULA FOR D76-ECO

This formula for D76-Eco can be used in the exact same manner as Kodak's D76 original formula.  You can refer to Kodak's data sheet for all relevant information regarding development times, etc.  I also the same formula that I use to make D-23-Eco Accelerated.  You may want to read my article on how to make D-23-Eco developer and why you would want to explore this as a developer choice.  

D76-ECO FORMULA

  • Distilled Water (125F/52C).....750ml
  • Metol.....2.5g
  • Sodium Sulfite.....100g
  • Borax.....2g
  • Distilled water to make 1 liter

This formula credited to Grant Haist omits hydroquinone and increases metol by 0.5g. This formula prevents the increased contrast associated with the original D-76 formula during storage, but it does not prolong the shelf life. However, the most important point is that the use of this developer does not discharge hydroquinone to waste water.

The D76-E formula is recommended for one shot use at 1+1 dilution or repeated development up to 8 counts of 80 sq. inch of film per liter of stock strength solution through reuse with increased processing time (10 to 15% increase after each roll). Reused solution should be kept for no more than two weeks as decreased activity may be detected.  If you want to test the pH of your developer, you should aim for a target pH of 8.5 at 25 °C ± 0.05.  

Note: all of the chemical materials area available to order directly from Photographer's Formulary via their website. You should be able to source distilled water from your local resources.  

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WHY ELIMINATE HYDROQUINONE?

Hydroquinone is a carcinogen.  The chemical has been identified as both a potential clastogen and mutagen. A clastogen is a toxin that has the capability of cause breaks in chromosomes, cause sections of them to be destroyed, and to rearrange the sections and thus cause mutations which can lead to various types of cancer.  A mutagen is a material that causes mutations and damage in DNA. When the DNA is altered, it can cause any number of chain reactions that can negatively impact the health, including cancerous growth of cells and cell division.

Other than its use in darkroom photography, hydroquinone is still one of the most commonly used skin lightening agents on the market in the United States.  The ingredient has been banned due to numerous safety issues and serious toxicity concerns in Europe, Japan and several other countries. I am not a chemist, however, it is my understanding that hydroquinone in conjunction with UV light can magnify its toxicity.  

UNDERSTANDING THE ROLE OF FILM DEVELOPERS

The goal of film developer is to convert the latent image on the film made at the time of exposure.  Developing agents achieve this conversion by reducing the silver halides into silver metal.  The developer only acts on those particles of silver halides that have been exposed to light.

Black and white film developers typically consist of three main components: developing agent (e.g., metol), alkaline agent (e.g., borax), and a means to delay oxidation of the developing agent (e.g., sodium sulfite).  

Metol

Metol along with Phenidone (newer agent) and Hydroquinone are common black and white developing agents. Metol is an organic compound and a colorless salt.  Metol is known to be a good choice for continuous tone and has been widely used in commercial formulas for many years.  

The original D76 formula (see below) contains both Metol and Hydroquinone and is called an MQ developer. This combination of agents is known to provide greater developer activity since the rate of development by both agents together is greater than the sum of rates of developments by each agent used alone (superadditivity).  Hydroquinone is principally associated with its action as a reducing agent (reduces silver halides to elemental silver).  

Sodium Sulfite

Sodium sulfite helps to delay oxidation of the developing agents by atmospheric oxygen.

Sulfites, or sulfur dioxide, is most commonly used as a preservative in wines and foods due to its antibacterial and antioxidant properties. Consumption of sulfites in wine and food is generally considered harmless, except in people who lack the bodily enzymes to break them down during digestion.

Borax

An alkaline agent such as Sodium Carbonate, Borax, or Sodium Hydroxide are used to create the appropriately high pH for black and white film development.  

DISTILLED WATER

To eliminate foreign agents in your developer, I highly recommend that you use distilled water.  This also allows you to make the developer exactly the same, independent of the local water source.  

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KODAK'S ORIGINAL D76 FORMULA

To the best of my knowledge, this is the formula for Kodak's D76 developer:

  • Water (125 deg. F).....750ml
  • Metol (or "Elon").....2g
  • Sodium Sulfite, anhydrous.....100g
  • Hydroquinone.....5g
  • Borax, granular.....2g
  • Cold water to make 1 liter

Note: chemicals should be mixed in the order listed above in both formulas and development times listed by Kodak are based on 68F/20C. 

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Comments

Tim Layton Fine Art
Hi Larry, thanks for the comment and question. Have you read my article "How to Choose a B&W FIlm Developer?" - Here is the link. If this doesn't help, just send me an email and I am happy to share my thoughts. Article- http://www.timlaytonfineart.com/blog/2015/4/how-to-choose-a-black-and-white-film-developer
Larry Huhn(non-registered)
Tim, can you recommend a good source for comparison of developers? I have been bouncing around somewhat blindly between Pyrocat HD, D=76, and Rodinal. I would like to narrow my developer choices and try to refine my techniques for 120 and 4x5 film.
Josef(non-registered)
Hi Tim, your receipt without hydroquinone is interesting. I use D76 very often, it is my most favorite developer. Mainly in 1:3 dilution gives me very good results for LF and 120 rollfilms. Thank you for your advices.
Tim Layton Fine Art
Hi Sasha, thanks for your question. Any time you dilute developers from stock, the development time will always be longer. It all depends on the specific developer being used. In other words, there is not a linear relationship that is constant for all dilutions. The results at different dilutions will also be different. Typically the longer the development cycle, the highlights will be "better", and more general contrast as well. Many reasons to use dilutions with specific film and developer combinations. Thanks so much and please stay in touch. Tim
Sasha Krasnov(non-registered)
Hi Tim

Interesting formula! But what about developing times? Can development times be considered equal for 1:1 and 1:3 dilutions with the near the same result?
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