D-23 in the Real Darkroom: Why This Simple Developer Still Earns a Place on My Shelf

There are a lot of film developers I could use, but D-23 remains a staple in my darkroom for one simple reason: it does exactly what I need it to do without unnecessary complexity.

D-23 is one of the classic black-and-white film developers. Kodak published it as a soft-working, fine-grain developer with a simple formula that gives normal emulsion speed. In other words, it was designed to deliver clean negatives, gentle contrast, and a full tonal scale without a pile of extra ingredients.

That matters to me.

I do not need a developer that tries to do everything at once. I want a formula that is easy to mix, easy to understand, and capable of producing negatives with smooth tonality and controlled grain. D-23 gives me that. It also gives me room to shape the result through divided development when I want more control over contrast and highlight separation.

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First, an important clarification

When people say “D-23,” they are sometimes talking about two related but different things.

The original Kodak D-23 formula was published as a single-solution developer made with 7.5 g of Metol and 100 g of anhydrous sodium sulfite per liter, used straight. Kodak described it as a soft-working fine-grain developer for plates and films.

The version many photographers use today in divided development is a modified D-23. In The Darkroom Cookbook, Bill Troop and Steve Anchell describe a divided D-23 built around 5.0 g of Metol and 100.0 g of sodium sulfite in the first bath, followed by a separate alkali second bath. They note that later practice showed less Metol could still work well, which is why modified versions became common.

That modified divided version is the one I am talking about here.

Why I like D-23

What makes D-23 special is not that it is flashy. It is that it is restrained.

It is a Metol-and-sulfite developer. That simplicity is part of its strength. Photographers’ Formulary describes Developer 23 as a metol-based, semi-compensating developer that produces low to medium contrast negatives and is favored by Zone System users. Kodak’s own formula sheet described D-23 as soft-working and capable of normal emulsion speed.

In practical terms, that means D-23 is a very good fit when you want:

• fine grain
• smooth tonal separation
• controlled highlights
• a developer that is easy to mix from raw chemistry
• a workflow that can be adapted through divided development

For photographers who value tonality over punchy contrast, D-23 still makes a lot of sense.

The divided D-23 formula I use

Here is the modified divided D-23 formula:

First Bath

• Water at 125°F / 52°C: 750.0 ml
• Metol: 5.0 g
• Sodium sulfite: 100.0 g
• Water to make: 1.0 liter

Second Bath
Use one of the following in 1.0 liter of water:

• Borax, granular: 18.0 g
• Sodium metaborate: 7.5 g
• Sodium carbonate, anhydrous: 4.5 g

Development

• First bath: 2 to 3 minutes with continuous agitation
• Second bath: 3 minutes with 5 seconds of agitation every 30 seconds

This is one of the main reasons I like this approach. I can keep the first bath simple, then choose the second bath based on what kind of negative I want.

What the second bath actually changes

This is where divided D-23 becomes especially useful.

Troop and Anchell explain that in divided development, the first bath loads the emulsion with developing agent, while the second bath activates it. Because development exhausts sooner in the highlights than in the shadows, the process has a compensating effect. That is a big part of why divided developers are useful for holding highlight detail while still building density where you need it. They also note that borax is the least active accelerator, metaborate is stronger, and carbonate is stronger still.

In plain terms:

Borax
This is the gentlest option. It gives the finest grain and the least contrast. This is the one to consider when you want the softest rendering and the most restrained negative.

Sodium metaborate
This sits in the middle. It gives medium grain and low contrast. For many photographers, this is the best balance point when they want divided development without going too soft.

Sodium carbonate
This is the most active of the three options listed in this formula. It gives the highest contrast, the coarsest grain, and the greatest film speed of the three. If you want a more energetic negative, this is the one to test.

That one decision alone lets you tune the character of the negative without changing the first bath.

Why divided D-23 works so well for difficult scenes

One of the biggest strengths of divided development is highlight control.

Photographers’ Formulary explains the basic mechanism clearly: after moderate development in D-23, the film is transferred without washing into the alkaline second bath. The developer absorbed in the emulsion is then activated, allowing development to continue more in the shadows while increasing the highlights less. The result is lower contrast overall.

That is why this kind of workflow can be so useful in bright, contrasty situations. You are not relying only on time and agitation to hold the negative together. The chemistry itself helps compress the scale.

For anyone printing in the darkroom, that can be very attractive.

Mixing notes that matter

With simple formulas, the small details matter more than people think.

Photographers’ Formulary recommends starting with warm water around 48°C / 120°F, adding only a pinch of sodium sulfite first, then dissolving the Metol before adding the bulk of the sulfite. Their instructions specifically warn that if too much sulfite is added too early, the Metol will not dissolve properly. They also recommend gloves, splash goggles, a dust mask, and good handling practices when mixing raw chemistry.

That is the kind of detail worth paying attention to. A simple formula is only simple if it is mixed correctly.

Practical handling notes

A few practical points stand out from the sources.

Do not presoak the film and do not rinse between the first and second baths when using divided development. Keep agitation gentle and keep the temperatures of all solutions consistent. Troop and Anchell note that divided development is less temperature-critical than single-solution development, but they still recommend keeping the baths aligned, roughly in the 68°F to 80°F / 20°C to 27°C range.

Photographers’ Formulary also states that a full, tightly capped bottle of Developer 23 working solution has about a six-month shelf life, and that Metol deserves special caution because some people become sensitized to it.

My bottom line on D-23

D-23 has earned its place in my darkroom because it is honest chemistry.

It is not complicated. It is not trendy. It is not trying to impress anyone. It is a straightforward developer that gives me fine grain, smooth tonality, and a high level of control when I want to work in a slower, more deliberate way.

That is exactly why I keep coming back to it.

And when I want even more control, the divided version gives me a clean way to steer grain, contrast, and highlight behavior through the second bath choice. For photographers who care more about the quality of the negative than the hype around the latest formula, D-23 still deserves serious attention.