Kathleen Bishop


Caffenol CM+i (or CM if you leave out the salt) for roll and sheet film

Plastic Tanks



1 roll of 35mm film

2 rolls 35mm film OR one roll of 120 film


300 ml


Wash soda






Vitamin c







Metal Tanks



1 roll of 35mm film

2 rolls 35mm film OR one roll of 120 film




Wash soda






Vitamin c







This recipe and time chart is tested for Kodak TriX film shot at the box speed of 400ISO.


For 100 speed films leave out the salt, all other ingredients are the same, developing time is the same in general, see chart at, but do some experiments of your own as info varies depending on where you look!) If using a new film, I recommend shooting a test roll and developing to confirm results. I have used the above formula with some 100 speed films, and I was happy with the results, although they recommend leaving out the salt. It’s the restrainer that prevents fogging for high speed films, and is likely not needed for lower speeds. 


Beaker 1          

½ the water

Arm & Hammer Washing Soda


Beaker 2

½ the water

Folger’s Instant Coffee, stir 1 minute

Vitamin C powder, stir until no fizz

Iodized Salt, stir 1 minute


After this, combine the beakers


Developer- 10 inversions, then 3 inversions every minute

Stop- WATER ONLY!!!!! Dump and fill twice. Agitate constantly one minute

Fix- 5-10 min (5 for Ammonium thiosulfate and 10 for sodium thiosulfate)

Wash 15 minutes

Photo Flo as usual, or use a drop of dishsoap (Dawn brand works very well in distilled water)


Times for Kodak Tri X 400 film:

68 degrees  15 min

72 degrees  11 min

75 degrees  9 min

76 degrees  8 min


for 4x5 tank 60 oz (Yankee tank) Multiply the amount for 2 rolls by 3 

Water 1800ml (=60 oz)

Arm & Hammer Washing Soda 117g

Folger’s Instant Coffee 72g

Vitamin C powder 30g

Iodized Salt 18g


What the ingredients do:

Coffee- Caffeic acid is the active ingredient. It is similar to Pyro- a compensating developing agent

Vitamin C- ascorbic acid (changes to ascorbate when washing soda is added)- similar to hydroquinone, a high contrast developer. Ascorbate is used in Kodak’s XTol developer.

Washing soda(sodium carbonate) alkaline agent that raises pH to activate developing agents

Iodized salt- restraining agent that reduces fog by slowing the reduction of silver halides on the film

Note* Caffenol must be mixed fresh and used within a few hours. It is only used once and then discarded.

Note* If you use brands other than those listed results may vary. Also different batches of coffee may vary in their strength!

Note* If you are trying different recipes, this Washing soda is a Monohydrate. Some recipes, especially from European countries may use a decahydrate or anhydrous, depending on what they sell in that country. You would need different amounts in that case. Most recipes that list by weight are from Europe, so you need to multiply the washing soda by 1.2 to get the equivalent amount assuming the recipe is for anhydrous.  

Note* Coffee MUST have caffeine! Caffeic acid is the developing agent!!!


Caffenol for Paper  

16 oz water

3 tsp Washing Soda

6 tsp Coffee

1 tsp vitamin c


Mix one ingredient at a time, in the order listedin your print tray (or a beaker)


Developer- 2-3 minutes


Fixer 2-10 minutes (2 for Ammonium thiosulfate and up to 10 for sodium thiosulfate)

Wash 15 minutes (this assumes RC paper- if you use FB paper follow those fixing and wash steps)



Sodium Thiosulfate (mostly odorless fixer option if you rinse your film/paper well before putting in the fixer bath)

 1000 ml water

240 g Sodium Thiosulfate (pentahydrate) crystals

 (or for the 4x5 tank 2000ml of water and 480 g Sodium Thiosulfate)

Use WARM water to mix- the chemical will drop the water temperature when mixed, and needs to be at room temperature to be used right away. It also dissolves more easily in warm water.

NOTE: Make sure you thoroughly rinse off the developer with WATER before placing in the fixer.When sodium thiosulfate mixes with acids, it gives off sulfur dioxide gas- not very pleasant stuff, and not good for you either. I change my water bath every few prints for this reason, and also it keeps the fixer fresh for longer. The more developer that gets into the fixer, the faster the fixer will exhaust, so rinse, rinse, rinse well with water!

NOTE: This fixer has no preservative added, so it is recommended to mix fresh for each use and discard. 


I store and reuse this fixer for several work sessions. Some sources say it won’t last, but mine seems to do ok. It does not keep for long periods of time. Ansel Adams’ Plain Hypo contains Sodium Sulfite as a preservative, but this chemical is hazardous, so I have never added it for that reason. He also notes that Sodium Sulfite prevents breakdown of the thiosulfatein the presence of acid; since we are not using an acid stop bath, as you do in conventional developing, it may not have much usefulness for this process anyway. You can consult his recipe if you are interested in this, but I have no experience with this formula. It is in his book “The Print” on page 194. 

Check your fixer by putting a piece of film leader or scrap (film can be exposed, do this in full room light) into the solution. Note the time it takes to clear the film (the milky color should disappear and the film will be clear).

Your fixing time is TWICE the time that it takes to clear.


Note* You need the Pentahydrate version of Sodium ThiosulfateIf you buy the anhydrous, you have too strong of a mixture. Photo supply houses should be selling the Pentahydrate but check the label. It should look like large crystals, not a fine powder. Freestyle Photo, B&H Photo and Bostick & Sullivanall sell it.


You can of course also use normal fixer (Ammonium Thiosulfate). It is not odorless though and slightly more toxic. It will fix in about half the time of the Sodium Thiosulfate.


My Version of Plain Caffenol- good for developing Litho film(gives increased tonal range, lower contrast)

Develop film at least 5 minutes, then water stop and fix as usual

(You can do this under red safelight and inspect the film while developing)


Water 12oz

Washing soda 2tsp

Coffee 4tsp


You may want to try a slightly diluted version of this formula for different tonal ranges. More concentrated formula=more contrast, less concentrated=less contrast. Develop for about 5-10 minutes depending on the results that you would like to achieve.


Anti spotting agent for film

Add one drop of Dawn dishwashing liquid to distilled water in your tank. Distilled is highly recommended for this step, as other water may leave spots on the film


Chemical Safety

-Keep separate containers of coffee, salt and vitamin c from the ones you eat/drink out of. Label them as such.

-Do not mix coffee or vitamin C (which are acids) with sodium thiosulfate. This will release sulfur dioxide gas. It is recommended to store your fixer separately from the other ingredients.

-Always thoroughly rinse your film or paper before putting it in the fixer to make your fixer last longer and prevent the release of sulfur dioxide gas. (this is true whether you use ammonium thiosulfate or sodium thiosulfate) 

-The addition of washing soda to the caffenol mix causes it to give off carbon dioxide gas (this is the signature “dumpster coffee” smell of caffenol. Always use adequate ventilation in the room for this reason, as this gas will displace oxygen in the room.

-It is not recommended to use ingredients of suspect provenance that may contain impurities. 

-Washing soda is a strong caustic. Wear goggles or safety glasses and avoid skin and eye contact. If you get it in your eyes rinse for at least 15 minutes and seek medical attention. 

-Always read the safety data sheets (SDS) for any chemicals you are using BEFORE you use them, even if they are household chemicals. They can have significant hazards on their own or when mixed with other chemicals.

-If you are asthmatic or sensitive to sulfites, you may not want to use these chemicals. They can produce a serious adverse reaction in these groups of people.


Sample supplies for a small darkroom

-Trays- recommend ones with a ribbed bottom for ease of lifting paper/film)

-Tongs- metal or bamboo (keep bamboo ones dry when not in use to prevent warping)

-HEPA filter- I have a small Holmes model

-Vent fans to bring in fresh air and vent out exhaust

-Safelight- any low wattage red bulbs will do, under 15 watts

-Squeegee for prints

-Squeegee board- a plastic cutting board works well

-Print washer- Patterson makes nice ones that hook to most faucets, or a tray may be used

-Developing tank for film, optional. Yankee has a nice one

-Timer and light source (enlarger or bare 5 watt bulb, LED source)

-contact printer (optional) can be foam and heavy glass on top

-Multigrade filters (optional)

-Digital thermometer


-Chemical containers

-digital gram scale

-plastic spoons

-disposable bowls for weighing chemicals

-paper towels

-tray tables for holding developing trays (Walmart has small ones)

-stirrers for mixing chemicals

-plastic storage containers 


-clothespins and drying line