Developing Kodak T-Max P3200 in Caffenol 

With Baking Soda, Vitamin C Tablets, and a Salt Mixture as a Fixer

7 min read by
Figure 1. Instant coffee weighted for the developer mixture.
Figure 2. Crushed vitamin C pills (bottom-left), vitamin C mixture (bottom-center), and salt developer (bottom-right).
Figure 3. Checking the temperature of the Modified Caffenol-C-H developer.

Over the holidays, my brother delighted me with his interest in our dad’s old film camera, FED 5B.

I handed him a roll of Kodak T-Max P3200 that he shot indoors. It was his first time with a film and a rangefinder camera; he chose to eyeball his exposures.

This recipe is a result of our brief research, imperfect technique, and limited prior experience developing film. Nevertheless, it accomplishes a few things that may be useful if you need to process a high-ISO film without access to a lab or photographic chemicals.

Our scenario involved holiday photo store closures, a dark indoor setting, with access to Kodak T-Max P3200, home developing tools, and a scanner.

What does this recipe accomplish?

This recipe will develop high-ISO black and white Kodak T-Max P3200 film at box speed, using chemicals found in everyday grocery store items. This includes the fixer step, which only requires table salt.

The drawbacks I’ve encountered with this recipe are the dense-looking negative, a long fixing time (overnight soak), and grainy results.


☕️ 40g of instant coffee.

🧂​ 20g of table salt (iodized) for the developer plus 300g for the fixer.

💊 16 vitamin C pills containing 1000mg each. If you get the powder in pure form (linked), you can skip the steps requiring you to crush the pills in a Ziplock bag.

📦 150g of baking soda.


You’ll need an oven, access to running water, a Patterson developing tank, a kitchen scale, a Ziplock bag, coffee filters, a fine-mesh strainer, a 1L measuring jug, a stopwatch, CineStill Cs temperature control system or similar and/or a thermometer, an optional 5L plastic tub, and two clean containers/bottles that can hold 1.5L of liquid each.

Figure 4. Baking soda (left) and washing soda (right) compared.

Modified Caffenol-C-H developer.

This recipe is based on the Caffenol-C-H formula from The Caffenol Cookbook. But instead of using 1g of potassium bromide (KBr), we’ll be using 20g of table salt, as suggested by Josh Vickers. We will also convert baking soda into washing soda since the former is easier to find in pure form. And finally, instead of vitamin C powder, we’ll be using tablets, which are also more accessible; if you’ve got it as a powder, you may skip a few steps.

✪​ Note: The difference between baking soda, NaHCO, and washing soda, NaCO. The heat will cause a reaction, 2NaHCO → NaCO + CO + HO.

1. Set your oven to 425℉/220℃ and place about 150g of baking soda on a sheet in a thin layer to bake for 2 hours. Once ready, it’ll look slightly finer, although it may be difficult to tell the difference (see Figure 4 above).

2. Your bottle of vitamin C tablets will tell you how much ascorbic acid is contained in each pill; calculate a total of 16g of vitamin C/ascorbic acid. Crush them in a Ziplock bag into a fine powder and mix carefully with 250ml of warm water in a bowl.

3. Strain your vitamin C mixture through a fine mesh and then a coffee filter. This may take a while.

4. Mix 54g of the washing soda (that you made by heating baking soda for 2 hours) with 250 ml of warm water.

5. Mix the washing soda mixture with the vitamin C mixture. In our case, it caused a reaction that formed white solids, which we strained again and then poured into a measuring jug.

6. Add 40g of instant coffee and mix thoroughly.

7. Top up with warm water to 1L, mix, and add 20g of table salt.

8. Let the developer cool to 20-24℃. We used ice and water in the 5L plastic tub and CineStill Cs Temperature Control mixer to make a water bath where we submerged the sealed developer bottle.

Salt fixer.

Mix 300g of iodized salt with 1L of warm water. Some salt may remain undissolved, which is OK.

Note: Further discussion and the original suggestion for the salt fixer can be found here.

Developing time, agitation and temperature.

Pour the developer into your Patterson tank with the film reel(s) and set a timer for 19 minutes. Make sure that your developer is at 20-24℃.

Start with ten inversion cycles for agitation and then do three inversions every minute until the time’s up.

Pour out the developer. The Cookbook authors advise not reusing it.

Fill your tank with the salt fixer, agitate ten times and then let stand for 12-48 hours. To speed things up, we heated ours to 42℃ and allowed it to cool for 10 hours before the final rinse.

Rinse, then take out your film and let it dry before scanning.

Results and discussion.

I did not think we’d see any results from the negatives once I hung them to dry. They looked densely brown with barely visible silhouettes.

Densely-brown negatives out of Caffeenol developer mixture.

Later, someone confirmed that this is to be expected with Caffeenol recipes. And thankfully, my scanner was able to pick up a decent amount of detail from the film.

That is not to say that I’m completely satisfied with the results. The images appear exceptionally grainy, significantly more than the results I got from T-Max P3200 developed in Ilford DDX by The Lab.

Although it’s fair to add that I also had P3200 developed by The Lab a few years back with a 1-stop pull, which caused some additional graininess.

I’ve also noticed that many of the images appeared under-exposed, which may be the result of the approximate metering or improper development times. Others’ results in slightly different mixtures, posted online or shared with me on Twitter and Mastodon, also showed large grains.

I used the PrimeFilm XAs scanner, which has a DMax of 4.2 (meaning it can work with very dense negatives).

Kodak T-Max P3200 in modified Caffenol-C-H developer and salt fixer for 19min at 20℃.
Kodak T-Max P3200 in modified Caffenol-C-H developer and salt fixer for 19min at 20℃.

And here are the respective samples of professionally-developed Kodak T-Max P3200 by The Lab in Ilford DDX:

Kodak T-Max P3200 in Ilford DDX, pulled 1 stop by The Lab.
Kodak T-Max P3200 in Ilford DDX by The Lab.

I haven’t tried replicating the results; thus, if you’re planning to do this, please be aware of the experimental nature of this process.

I look forward to your thoughts and suggestions in the comments below.