Darkroom Digest: Exploring Metol Developing Agent and The Historic D-23 Developer Formula

September 30, 2016  •  4 Comments

Before I discuss Metol specifically, I thought it would be helpful to provide a quick overview on the role of black and white 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 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 before Kodak discontinued it. Metol is a highly versatile developing agent and a standard that I keep in my darkroom.  I use Metol in my D76-E and D-23 formulas.  

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Part of Metol’s magic is that it slows down the development process, which in turn can result in lower contrast negatives.  Lower contrast negatives are thought to be easier to print.  Metol developing agent can create very sharp or fine grain images, but not both at the same time.  There are special cases, for example, when I know I am making platinum prints, I want a higher contrast negative so I use my D-76-Eco formula or Pyrocat HD.  If I am going to make a silver gelatin contact print, then D-23 is my personal choice for a lot of my negatives.  

The famous photograph by Ansel Adams "Winter Sunrise from Lone Pine" was exposed on Isopan film and developed in D-23.  "I used my 8x10 Ansco view camera with the 23-inch component of my Cooke Series XV lens with a Wratten No. 15 (G) filter. The film was Isopan, developed in Kodak D-23" - Ansel Adams


The formula to make D23 black and white developer is about as easy as it can get for photographers.  

D-23 is very similar to D-76 minus the Hydroquinone, whose presence speeds up development and Metol is a better choice for the environment and people too.  I like Borax as an accelerant versus Hydroquinone because Hydroquinone is a known carcinogen.  Hydroquinonel 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.  I call this formula D-23-Eco, mainly because the Hydroquinone has been removed from the formula.  The key takeaway for me about this D-23 formula is its eco-friendly nature and the lower contrast nature of the negative it creates along with the ability to create brilliant highlights with open shadows.  

D-23 hasn't been offered as a commercial product for decades, but that doesn't matter because it is super easy to make and in the section below, I share all of the reasons why I like the formula.  

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D-23-Eco-Friendly Formula & Process


  • Metol.....7.5g
  • Sodium Sulfite.....100g
  • Water to make 1 liter 

Process to Make D-23-Eco-Friendly Developer 

  • Heat 500ml of distilled water to 52C/125F
  • Dissolve 7.5g of Metol separately in small amount of distilled water
  • Add the dissolved Metol to 500ml of 52C/125F water 
  • Dissolve 100g of Sodium Sulfite in small amount of distilled water
  • Add Sodium Sulfite to 500ml of 52C/125F distilled water 
  • Add distilled water to make 1000ml 

Usage Notes

Use D-23-Eco at 20C/68F if you can and if not, make sure you adjust your development time accordingly based on your local temperature.  

I have found development times for D-23 to be very close to Kodak D-76.  As a starting point, you could refer to the D-76 data sheet or I highly recommend that you properly test your film/developer combinations so that you can establish a repeatable workflow that yields reliable high-quality results.

I have found that Ilford HP5+ and FP4+ develops to my satisfaction for contacting printing at 9 minutes with the 1:1 dilution at 21C.  I use HP5+ sheet film on a regular basis in my 8x10 and 11x14 large format view cameras and FP4+ in my 4x5 and 8x10 cameras.  I really like that I can mix the amount of developer that I need on demand from the raw materials.  

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Alternatives to Standard D-23 Formula

Denise Ross hosts "The Light Farm" website where she writes about her amazing work and adventures with classic darkroom processes.  I wanted to share this specific page with my readers because Denise uses less Metol in her formula and she shares a tip on how to use Borax as an accelerant in a different formula.  I like the Borax option when developing my dry plates and know that I am going to be making platinum prints.  Borax acts as the accelerant and by modifying the amount of Metol and adding Borax, this is effectively my D-76-Eco formula.  

I have created a short list of why I like D23: 

  • D-23 has only 2 ingredients making it very simple and highly effective.  
  • D-23 is a fine grain developer with excellent tonal separation, good film speed and it produces very clean negatives.
  • D-23 is incredibly easy to make.  You can mix it fresh from powder every time making it a great choice for any photographer that is not developing on a regular basis. This is a perfect developer for large format photographers. 
  • D-23 can be diluted 1:1 making it even cheaper to use. By diluting to 1:1, you can get longer development times which comes in handy when doing development by inspection.  
  • D-23 is a slightly slower developer, which means it has good compensation and less risk of "runaway" highlight values.

Quotes from Stephen Anchell (Darkroom Cookbook, 1st Ed.)

"A developer of the semi-compensating type using either Metol or Pyro alone in a solution of relatively low pH is capable of producing brilliant high values, full-scale mid-tones and shadows (e.g. Kodak D-23 and Kodak D-1, ABC Pyro, especially Edward Weston's variation)." - pp. 42

"Kodak D-23 is a semi-compensating developer that produces fine shadow values while retaining a high emulsion speed... Note: This developer produces negatives of speed and graininess comparable to Kodak D-76, without D-76's tendency to block highlights. " - pp. 150

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Tim Layton Fine Art
Hi Jim, I am in the process on a daily basis of writing those articles, so your question is very timely. Just check back every day because I will be posting my formulas for fixers and stop baths too in addition to some in-depth articles on the reasons I make specific choices. Stay in touch. Tim.
Perhaps you've done this and could point me to the article, but if not, could you describe your process and the other specific formulations (fixer etc.) you use in development?. I have been using R5 monobath with 120 and 4x5 film because it's so easy, but the tonal range seems a bit limited.
Tim Layton Fine Art
Hi Rolf, thanks for your comment. Yes, it is 7.5 vs 75. I had a buddy call me this morning and let me know about the typo too! So, thanks for the proofreading and keeping me in line... :) Stay in touch. Tim
Rolf Schmolling(non-registered)
Hi Tim,
just a question for clarity: you mention above 7.5g of Metol but in the instructions how to make write 75g Metol… what is right? Very interesting topic! R.
No comments posted.

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