Updated: Nov 14
Part 1 - Kodak D-23
In this new series of blog posts, I will take you through how to compound your own black and white developer formulae from raw chemicals, which will allow you to explore the varied effects possible when home-developing black and white film. You don't need to be a chemist to perform any of the steps, just moderately careful with some of the ingredients as they can be a little bit nasty sometimes.
We'll start off with a fairly simple developer - Kodak D-23 - a metol-sulfite formula.
More film development articles:
A Short History of Kodak D-23
Kodak D-23 is a black and white film developer that was introduced by Kodak in 1944. It is a simple and economical formula that consists of only two chemicals: metol and sodium sulfite. Metol is the developing agent that reduces the silver halides in the film, while sodium sulfite is the preservative and accelerator that creates an alkaline environment for metol to work. As development proceeds, bromide is released from the film and acts as a restrainer, preventing overdevelopment of the highlights.
Kodak D-23 is a soft-working developer that produces fine grain, low fog, and soft contrast with deep blacks in the shadows. However, Kodak D-23 is no longer produced by Kodak, so it needs to mixed up from raw chemicals at home. One advantage is that once mixed up, the stock solution has a long shelf life, thanks to the high sulfite content.
As a sulfite-rich formula, D-23 is a highly solvent developer which reduces the appearance of grain - at the expense of sharpness. You can theoretically get around this by using a lower concentration of D-23 as your working solution (i.e. developing in 1+3 dilution rather than stock) which then reduces the amount of working sulfite, allowing you to achieve the compensating effects that D-23 is prized for, without ending up with mushy grain.
Kodak D-23 has been a popular developer among many photographers for its simplicity, economy, and versatility. It has been used by famous photographers such as Ansel Adams, Edward Weston, and Henri Cartier-Bresson.
Why Make Your Own Kodak D-23?
Kodak D-23 is no longer available pre-packaged, so mixing it yourself is the only way to experience the effects of this developer and achieve results you might not be able to with off-the-shelf developers that are available today.
When using the stock solution, you will find it a soft-working developer with fine grain, low fog, and soft contrast characteristics, and deep blacks in the shadows. When D-23 is diluted 1+1, you find you have a sharper developer that increases the acutance and edge contrast of the image, while exhibiting some compensating effects. And diluting D-23 1+3 (my personal favourite), you get an acutance and fully compensating developer that enhances the local contrast and detail of the image, especially in the highlights. It also reduces the overall contrast and tonality of the image, making it suitable for scenes with high contrast. It requires quite significantly longer development times and decreases the film speed reasonably compared to the stock solution.
My main use for D-23 is for its compensating effects in the 1+3 dilution, typically combined with minimal agitation development pattern which compounds the acutance and local contrast effects.
If you’re enjoying this, please do consider subscribing to Michael Elliott’s weekly newsletter. It has lots more blog articles, photo features and more.
Equipment required to mix Kodak D-23
You will need the following equipment:
a 1 litre Pyrex (or similar) jug
two smaller containers for measuring out the metol and sodium sulfite
a chemical mixer stick
a set of scales that is accurate to 3 decimal places
an accordion bottle to store the stock solution once compounded
WARNING! As a responsible person, I should warn you that mixing chemicals can be dangerous. Always wear suitable eye protection and gloves. If you spill any of the chemicals on bare skin, wash thoroughly under running water for a minimum of 10 minutes, and if prolonged irritation occurs, seek medical assistance. If any chemicals splash in your eyes, wash under running water for 15 minutes and seek immediate medical assistance. If you swallow any of the chemicals, do not induce vomiting and drink lots of clean water, then seek medical assistance. In all cases, when seeking medical attention, take all containers with chemicals you were compounding with you.
With that out of the way, on to the recipe!
Kodak D-23: The Recipe
The formula for Kodak D-23 is incredibly simple (and one of the reasons I chose it to start off this series). It consists of 3 ingredients - metol (or as Kodak called it, Elon), sodium sulfite and water, compounded in the following quantities and order:
- 750ml water at 50C/125F
- 7.5g metol,
- 100g sodium sulfite
- water to make 1 litre.
Metol is suspected to be a skin sensitiser so please be careful when handling it.
Warm 750ml of water to 50C/125F in a beaker. In another container, measure out 7.5g of metol and in a third container, measure 100g of sodium sulfite.
Now, ordinarily you would mix the ingredients following the order of the ingredients list above strictly; however, add a pinch of sodium sulfite first as this prevents the metol from beginning to oxidise in the water (you wouldn't add the entire quantity of sodium sulfite first as it would then make it impossible to get the metol to dissolve). Stir until completely dissolved.
Add the entire quantity of metol slowly while stirring. Ensure that all of the metol is completely dissolved in the water. If you put enough sulfite in prior to this, the water should not change colour too drastically.
Add the remainder of the sulfite and stir until dissolved.
Pour into your accordion bottle. Allow to cool and then use.
That's it, it's really that simple.
Some Development Times with Kodak D-23 and Various Films
Having used this developer primarily in 1+3 dilutions, most of the times below will be for that dilution. Also note that these are developed to personal preferences for contrast and density - one of the joys of developing your own film! - so you will likely want to play with these times until you achieve the result you want. They can be used as a good starting point. The Massive Dev Chart also has some good starting points for developing with stock solution D-23.
Agfapan APX25 - 20 minutes
Fuji Neopan 400 (at EI50) - 17 minutes
Fuji Neopan 400 (at EI200-400) - 20 minutes
Kentmere 400 (at EI200) - 23 minutes
Kodak Plus-X Pan 125 (at EI80) - ~1+4 dilution, 23 minutes
These have produced incredibly fine results for the relatively fast, relatively grainy films. The 1+3 dilution avoids the grain clumping that would happen with stock D-23 and so you still maintain a sharpness while effacing the natural grain to a certain degree. With the APX25, the inherent contrast was brought down to more manageable levels, and with the long expired Plus-X Pan, the fog was minimised.
There are some more suggestions on how to use D-23 by Derek Watkins - some of my timings are derived from his work.
Taking it Further - Divided D-23 and Replenished D-23
I have gone into some of the ways to use D-23 as a one-shot, single part developer. There are, of course, countless other ways to use D-23, for instance, as the first bath in a Thornton Two Bath process, or as a replenished developer. I haven't personally taken the time to use either of these approaches, but they have their uses and adherents, and some swear that replenished D-23 is God's greatest gift to photography... I'll reserve judgement on that!
Final Thoughts - A Great Entry into Mixing Your Own Developer Up
In summary, this is a developer that I would highly recommend as an entry into the world of mixing up your own solutions from raw chemicals. As a developer it is a pretty good all-rounder, though I use it specifically in its 1+3 dilution to act as a highly compensating developer, while maintaining acutance and enhancing local contrast effects.
It's easy to mix, useful for most films, though with some you do incur a slight speed loss, and produces great results time and time again. It wasn't a favourite of Ansel Adams for no reason!
You can follow Michael Elliott on:
MichaelElliottPhotographer on Facebook
MichaelEllio77 on Twitter
michaelelliottphotography on Mastodon
michaelelliottphotography on 500px
michaelelliottphotography on Flickr
mephotographer on Behance
If you enjoyed this, please do consider subscribing to my weekly newsletter. It has lots more blog articles, photo features and more.