How to Process C-41 Color Negative Film at Home, From Start to Finish

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I know there are a few guides out there for home processing, some of which were instrumental in helping me get over my fears. All of these other guides seemed to be a little incomplete and that lack of detail made me wait longer than I should have before taking the plunge. In reality, it’s easy to do your film at home. Let me show you!

The Tank

The first thing you are going to need is one of these magical things:

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This is your ticket to daylight processing. No need for any darkness in your “darkroom” with one of these. The reels are convertible. In the small size they take 35mm film. Give one a twist and it extends to a size that takes 120 or 220 film. They fit on the central column as you can see in the picture.

So this one tank lets you do two 35mm rolls at once or one 120 or 220 roll. However, you can also process four sheets of 4×5 film at once in the tank if you remove both reels (you need to keep the central column to keep it light proof).

I bend them gently in half (emulsion side facing inwards) and hold the “tacos” together with a rubber band. I then arrange them around the central column.

Here is a 4×5 film “taco” and four of them arranged in the Paterson tank:

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The Chemicals

Look on an online camera shop for “C-41″. You will find they sell a three chemical powder kit called a “Press Kit”.

It may be by Jobo or Tetanol or something else but but if it is a three bath powder kit selling for around $30 then that’s the one!

You mix up the chemistry into three containers and each will be one litre when mixed. You need airtight containers which plastic containers are not (they breath), so I recommend glass.

A narrow neck will be a big help in keeping air out and a wide base will be a big help in not tipping them over when working. In fact, you could do a lot worse than the bottles I found in a discount store locally for a few dollars brand new:

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They came with some cheesy glass stoppers that were not airtight. I replaced them with some laboratory stoppers that are. You will notice that the glass is not brown or opaque. That hardly matters. I store them in boxes in a dark cupboard. Light, heat and oxygen are the enemies of your chemistry. If you can keep them airtight, cool and dark they will last longer than your nerve to keep using them! My current batch was mixed more than six months ago.

The Glassware

The next thing you need (in addition to a bathroom with a bath and sink) is a good thermometer (or two) and a good funnel. Don’t cheap out here. I must have spent close to $20 on decent lab quality thermometers and a good lab quality glass funnel. I also have two beakers that I found I didn’t need but they come in handy for holding the thermometers and funnel.

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C-41 chemistry is very temperature sensitive. The whole thing should take place at 39 degrees C plus or minus 1 degree. Of this the most important stage is the Development stage. The later stages of Blix and Stabilise are not as critical. This is where your good thermometers and bathtub come in. I chose thermometers that were long (for easy use and easy reading) and that were fast. You can test this in the shop. Squeeze the bulb and as long as you are not a vampire the temperature should start going up. Let go and it should come back down. The faster this happens the better. I found these “spirit” thermometers are pretty quick.

The funnel is necessary because the chemistry is re-usable. You will be pouring the chemistry back into the bottles and you will want to do it quickly. Pretty hard without a good funnel.

The App

LabTimer. You really want this app for your iPad or something similar. Go ahead and download it while you are reading this. It’s free. Go ahead and set it up with the following four timers:

  • Developer: 3:30
  • Blix: 6:30
  • Rinse: 3:00
  • Stabiliser: 1:30

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All downloaded and set up? We’re nearly ready! Go string up a line across the bathtub or shower stall and get some paper clips or metal office clips ready for when the film is done. It needs to be close to head height because a 36 exposure roll of 35mm film is pretty long.

The Procedure

Right, let’s soup some film!

Here’s an action shot taken during an actual processing run. Sorry for the crummy quality, anything done in the middle of a run has to be done in a limited space of time as we will cover in a minute:

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(That’s my wife’s Hello Kitty bubble bath, I’d like to point out.)

Here’s the decode to that picture: On the left is my iPad in a non-slip silicone case with LabTimer running. The Blix bottle is on the ledge there with very little chemistry in it because all that chemistry is in the Patterson tank with my roll of 120 Kodak Portra 800. The Developer bottle is back in the bath water keeping warm and has one of my thermometers leant against it telling me the temperature of the water bath. The Blix bottle has my funnel in it because I will be pouring back into it when the timer goes off.

Preview over.

Loading The Film

First step needs to be done IN THE DARK. I know, it’s a drag. After this step it’s all daylight, though so don’t fear. If you have a changing bag then use it. For the longest time I loaded my film in a room with no windows in the cupboard under a bedsheet at night. The room may not have been perfectly dark but the cupboard in the dark was pretty dark. Under the sheet it was even darker. Darkness is like security, it’s all about layers. Practice the film loading in the daylight with junk film or a roll you sacrifice for the purpose before you try it in the dark. There is a knack to it but it is pretty easy. For 35mm film make sure you cut off the “tongue” so you have a square edge. It will make life much simpler!

The reels twist and have a little ratcheting motion in them. What you need to do is feed the film into the outer edge of the spool at the start of the spiral and feed it in a few inches. After that, you simply twist the sides of the reel back and forth and it will draw the film in. When you get to the end of the roll you need to cut off the end (for 35mm) or detach the end from the backing paper (120 film). Keep feeding the film into the spool a few inches past where it is all in.

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Once the film is on the reel or reels put them on the central column inside the tank and install the inner funnel shaped lid and click it into place. I usually stick my little finger in the hole in the middle and make sure I can feel the central column before I go out into the light. The tank is light tight with the funnel lid on and central column inside. Nevertheless you can still pour liquids into and out of it. This is the genius part!

That’s it for darkness! Everything else is in the light.

Final Preparations

Proceed to your darkroo– er, bathroom. The rubber top lid of the tank should be somewhere where you can reach it. Now you are ready to get film wet. Once you get the film wet you are committed so make sure all is ready. Here is the checklist:

  1. Chemistry bottles are sitting in the bathtub in water of the right temperature. I usually heat the bath up about four degrees too warm and stick the bottles in as I’m first getting ready. When I have the film loaded in the tank and everything else ready it is usually close to the right temperature. If you need to fine tune just add a little hot or cold and stir it around well. You want a bath that mostly surrounds the bottles but isn’t so deep that your developing tank with film and fluid in it is going to try to float.
  2. Line and clips for hanging wet film is strung and ready.
  3. iPad in place with LabTimer open and all timers reset and ready.
  4. Funnel available as well as rubber top lid of for developing tank and in easy reach.

Time Critical Steps

Run the taps on your sink and adjust until the water running out of the tap is 39 degrees C or 40. When the temperature has stabilised put the tank under the tap and fill it almost full with the warm water. With the Press Kit chemistry the film should pre-soak for one minute at the temperature that will be used for developing. This gets rid of some of the anti-halation layer chemistry, softens the film and gets everything up to the right temperature.

After one minute dump the water. It may be all kinds of crazy colours so don’t be alarmed! It depends on the film brand.

Immediately next, start pouring the Developer chemistry into the Paterson tank. Fill it until you can see the fluid coming up through the funnel top. In other words, an inch or so from full. Too much chemistry in the tank won’t hurt but too little will leave some of your film undeveloped so don’t waste time measuring, just make it close to full.

Start the Developer Timer

Put on the top rubber lid and work the seal around the edge, rotating the tank as you do. Once you are sure the lid is fully on keep skooching the tank around in a circle until you see you have used up about 15 seconds of the time on the timer. Stick the tank in the bath water. At three minutes left you will pick up the tank for your first inversions. Here is how they go:

  1. Pick up the tank.
  2. As you are picking it up by the top get the other hand underneath so you have it top and bottom.
  3. Move it up in an arc and bring it down upside down as if you are trying to move all the fluid and contents from the bottom of the tank to the top.
  4. Reverse the motion bringing the tank back rightside up as if you were trying to move all the fluid and contents from the top of the tank to the bottom. This is one “inversion”
  5. Repeat the steps for a total of four inversions
  6. Put the tank back in the water

This “four inversions” exercise takes place at every thirty seconds and is essential to proper working of the chemistry with the film. Don’t skip it. And try to keep close to the right times. This is the tricky part because any housekeeping and so on you want to do during the process must fit into the gaps between one set of inversions and the next!

For example, here’s how I generally do the Developer stage:

  1. Pour chemicals into tank, start timer (3:30), fix lid, place tank in water
  2. First four inversions (3:00), tank back in water, place funnel in mouth of Developer bottle
  3. Second four inversions (2:30), third (2:00), fourth (1:30), fifth (1:00)
  4. Sixth inversion (0:30), remove rubber lid in preparation for pour, hurry to sink with rubber lid and rinse thoroughly then lay down ready for reuse
  5. Pour out Developer solution back into bottle (0:00)

Now some people will have you stress down to the second on these timings. As I said, you do want to get the inversions going pretty regularly and close to on time but if the total Developer time is 3:25 or 3:40 it isn’t going to make a huge difference. Nevertheless, do your best.

Here’s how I manage the transition from Developer to Blix: I try to start pouring the Developer back in the bottle very close to zero on the timer. You won’t be able to do it instantly since you are pouring close to a litre of fluid so just pour it as fast as you can without mess and don’t worry about the extra seconds.

Start the Blix Timer

When you have poured it all out pour the Blix in. Again, as fast as you can without mess you want to get the tank fairly full and then follow the same procedure as above with getting the lid sealed and hopefully in the water by fifteen seconds after you started the timer.

Here’s how I play the Blix stage:

  1. First four inversions come at (6:00). Put the tank back in the water and go run to the sink with the funnel and give it a good quick rinse and clean before putting it in the neck of the Blix bottle.
  2. Second set of inversions (5:30). Now you can put the stopper back in the Developer bottle and put it back in the water to keep warm.
  3. Third inversions (5:00). If you didn’t get any of the above housekeeping done yet finish it off now
  4. Inversions at 4:30, 4:00, 3:30, 3:00, 2:30, 2:00, 1:30, 1:00
  5. Last set of four inversions (0:30) and get the lid off and rinse it well. The Blix chemistry is somehow more of a pain than the Developer. It is more prone to leak past the lid and it takes a bit more rinsing to clean off of things. It also seems to generate a little pressure in the tank so I normally squeeze out a little air by pushing down on the centre of the rubber lid just before an inversion when Blix is in the tank. I find this leads to less fluid trying to leak out. Oh! Leave the tap running after you rinse the lid
  6. At the end of the time for Blix (0:00) pour the Blix back in the bottle and then take the tank to the sink and place it under a fast running tap. The water can be warm or cool.

Start the Rinse Timer

Let the fast running tap water fill the tank. Slosh it around as it is filling. When it is full dump all the water out in the sink shaking the tank as you empty it. Once empty immediately start filling again with the same sloshing motion. Keep doing this filling and emptying with a lot of motion until the Rinse timer goes off. The goal is to completely fill and completely empty the tank each time. This will get all the remaining chemistry off the film. When the timer finishes just dump the last tankful of water and turn off the tap.

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Start the Stabiliser Timer

The Stabiliser is the most relaxed of the chemicals. Pour it in and jiggle the tank for the first fifteen or twenty seconds then let it stand. Temperature doesn’t matter much at this stage so you don’t need to put it in the water. At the end of the time just pour it back in the Stabiliser bottle.

At this point I like to do a little final rinse with some distilled water. It just helps the film dry a little cleaner. I pour in a little distilled water and slosh it around and pour it out. I do this a few times with a small amount of water each time.

You are done! Feels good, doesn’t it?


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Take the reels out. One at a time pull the film gently off the reels and hang each with a clip from the line. You will need one or two clips at the top as well as one or two at the bottom. The clips at the bottom are weights because the film will want to curl around like a snake as it dries. The weights will keep it from running into other films and will help the water run off by keeping the film fairly straight.

When the film is dry you just cut it down and sleeve it.

Just a few notes about the drying stage. Try not to let anything touch the film whilst it is drying. It will be very soft and easily damaged at this stage. If anything should get onto the film panic! No, don’t panic. Get some distilled water right away and pour it liberally down the film. If you catch it right away the distilled water should wash off whatever got on the film without damaging it. Allow the film to dry again on its own. Don’t worry about the appearance of the film until it is dry. It is normal for it to look cloudy or uneven until it is dry.


Make sure you clean everything you used. If you rinse it well and dry it right away you shouldn’t need anything more than water to keep it all clean. Store it away from dust and it should be ready for next time.

Film rocks!  A photo I self-processed at home

Film rocks! A photo I self-processed at home

Congratulations! You’ve helped keep film photography alive!

About the author: Sam Agnew is a professional photographer based in Doha, Qatar. Visit his website here. This post was originally published here.

  • Mitch Labuda

    Mind the disposal of silver bearing chemistry

  • 12oclockboy

    this cant be good for you….or safe to pour down the drains..

  • DamianM

    Yankee makes 4×5 processing drums so you don’t have to “taco” them, and have to deal with uneven processing. only like 30 bucks for one of those

  • DamianM

    well what is?

  • ted_harmon

    FIY you can process two 120 rolls on one spool as long as the spool also takes 220 film (220 being twice as long as a 120 roll). You’d have to compensate with more developer. I’m unsure how you’d do that with C41, so far only souped BW (where Rodinal wants at least 5 ml of soup per roll of film). Also: Great article! I’ve been itching to try some color dev

  • ennuipoet

    The bleach fix is mildly caustic, but I’ve been getting on my hands for decades without injury. If you get some in your eyes, rinse for 15 minutes in cold running water. As for disposal, the small amount of chemical you are dumping is far, far, far, FAR less than the much more caustic household bleach people run out of their washing machines every day. The myth of color processing disposal comes from the old days of color slide chemistry, the current E6 process is as safe as C41. Also, in these days of digital there is so little chemistry going back into the environment it is a non-issue.

  • Sam Agnew

    Thanks, DamianM, but I’ve actually had very good results from my tacos. If you see my pics in the article of film hanging to dry you will see some nice even 4×5 sheets done in this very way. If I do ever decide to upgrade my 4×5 processing it will almost certainly be by upgrading to the three reel Paterson tank and adding the MOD54 insert. The Paterson stuff is modular and such good quality. I’m totally sold on the quality and convenience of their equipment!

  • Becca Gulliver

    Apologies for what seems like a silly question, but how do you know which side the emulsion is on when you’re loading in the dark?

  • Bosscock

    CAUTION – tank can pop lid

    The developer is warm and the gasses released in the process will make the lid of the developing tank pop quite easily. every minute of so “vent’ the tank by releasing the lid a little.

    My kitchen units have never been the same since I sprayed developer over the painted wood surface. I thought I’d wiped it all up till I got up the next day and saw the “developed” splashes everywhere, and it DOES not come off

  • Bosscock

    the 4×5 sheets will have notches on them depending on the film, keep notches at top and on right = emulsion towards you….

  • Sam Agnew

    Well, not to diminish the magnitude of such a potential incident you will be well placed to avoid it if you are following the steps carefully.

    The first and most important instruction is that fifteen seconds you are to spend skooching the tank around sealing the lid in a circular motion. It is easy to get the lid not pressed on all the way around but once it is all the way on I contend it doesn’t come off very easily.

    The second and nearly as important is to follow my instructions about having one hand on top and the other on the bottom as you do the inversions.

    As for the gas pressure, I don’t normally have any issue with the Developer stage with the Press Kit C-41 chemicals but I generally do with the Blix stage. As mentioned, I got tired of the minor dribbling of Blix at every inversion and have taken to pressing down in the centre of the flexible rubber lid a few seconds before each inversion cycle. This has the effect of “burping” the excess pressure out slightly and I get little to no dribbling this way. No need to actually lift the lid (and risk not resealing it properly) just press in the centre and the excess pressure will be released.

    Finally, and most importantly, this is happening in the bathtub! Cleanup should not be so difficult if you should happen upon disaster. So please do not perform this operation on antique mahogany surfaces!

  • Matthew Wagg

    There are chemical recycling places that take chems, Kodak has a paper on it on their website.

  • Alan Dove

    Good tutorial, and I love the “taco” trick for 4×5 – may have to try that. A few minor addenda:

    1. Do not rinse after the stabilizer. The stabilizer is a chemical (usually hexamine) that keeps the dyes in your color film from rotting. Rinsing after it will remove that protection. It’ll look fine at first, but a few years from now you’ll regret it. B&W film doesn’t use those dyes, which is why it doesn’t require a stabilizer step.

    2. Add a squirt of Photoflo to the stabilizer and use it at room temperature. Those two things will go a long way toward eliminating streaks. I also shake/spin the reel to get extra droplets off before unspooling it and hanging it up.

    3. The developer is really the only temperature-critical step, and it only lasts a few minutes. I don’t bother with a water bath for that reason. Just put the developer, blix, and a bottle of water for the pre-rinse in the microwave for a couple of minutes until it’s all up to 40C or a little higher (leave the stabilizer at room temperature). Put the thermometer in the developer, and when it’s just above 39C start your pre-rinse. You’ll be on the blix before the developer drops another degree.

    4. These chemicals are not particularly toxic, but they are irritants – they’re certainly no worse than things you probably use all the time around the house. Wear gloves and avoid breathing the powders as you mix them up, and you’ll be fine. The fixer, however, will accumulate elemental silver, which is toxic to all sorts of things in the environment. Check with your state DEP to see about disposal. My state (MA) is pretty persnickety about environmental issues, but even here it’s fine to dump developer and blix down the drain. Fixer has to be handled by a disposal company or taken to your town’s “hazardous waste day” drop-off. The latter is generally free, so there’s no excuse for doing this wrong. Just pour the exhausted fixer into a well-labeled gallon jug, and take it in whenever the hazmat day comes around.

    5. The chemicals are definitely reusable. I usually chicken out and mix a new batch after a dozen rolls and/or six months, but there are numerous reports of folks using them far longer than that with good results. Considering the (rising) price of good photo lab services, doing it yourself pays off very fast. You can also push or pull a roll at no additional cost.

  • Clarke

    Is there no increased development times for the speed of your film?
    If i’m shooting Portra 400 or Portra 800 I would develop them for the same amount of time? I tried getting a DEV chart for c41 films but I could not find it. Am I missing something? Hahah sorry if this sounds like a silly question but I just want to start doing my own colors.

  • John Mason

    Don’t, if you have a septic tank. Check with your local water department to see about their policies. Every area is different and some will have a heavy metal waste disposal drop offs, etc. Frankly as long as you aren’t doing large commercial type jobs, the amounts you dispose of are very small. That being said, you can recycle the silver out of your fixer or blix solutions with steel wool, and then dump the remaining water. It’ll take time (ie, there’s about 5grams of silver in one liter of used fixer), but you can collect up the silver and melt it down into a bar once you have enough :)

  • John Mason

    Entirely depends on the chemistry and the film. Refer to the manual that comes with the C-41 kit. You can push or pull the film in development but there again that depends on the film and the chemistry. The manual will answer most of your questions.

  • Sam Agnew

    C-41 is a very standard process intended for fully automated operation as in, for example, the automatic film processor of a 1hr photo lab. All colour negative film regardless of brand or rated speed will be properly processed at the times and temperature given above.

    It IS possible to push and pull process by varying the time and you will see some instructions for that in the sheet that comes with the Press Kit. However, colour negative film has such a broad exposure range that I would highly suggest in most situations just doing a standard development and then working out the final digital positive version the same way the lab does printing, by scanning it with more or less exposure. I routinely overexpose my colour negative film by many many stops and I give it all standard processing when I develop it.

    The only time I would ever vary the processing is if I had the idea that I had grossly underexposed a whole roll. In that case I might follow the instructions for a 1 stop push (or, more likely, just add a minute at the Developing stage). But remember, any pushing or pulling is for the whole roll (or both rolls depending what is in the tank). Therefore, again, I would almost always recommend standard processing.

  • Scott W

    Don’t you mean at the bottom right hand side?

  • Sam Agnew

    No. Bosscock is correct.

  • Red

    Thank you for this info. I have not processed film in years and you have reinspired me to get back into this hobby especially with my new love of medium format photography.

  • Curious User

    This is a great article. Thanks for putting this together. I have a few questions.

    During the pre-soak step, is agitation necessary? Is it bad to do so?

    I’ve read in other articles that you should agitate for the first ten seconds of the developer stage but you don’t do that. Is this a critical step? What is the advantage of agitating for the first ten seconds?

    For the blix step, I’m wondering the same about the first ten seconds. Should this be done? Should it be avoided?

    After the blix step, am I correct in thinking that the light-tight funnel on the developer tank can be removed? After the film is fixed, it isn’t sensitive to light anymore, correct? I ask because rinsing would be easier at this stage I would imagine.

    After the blix, should the film be inspected before continuing? I’ve read elsewhere that you can redo the blix stage if the film isn’t orange ( meaning the film didn’t get bleached well ).

  • Ajit Singh Birdi

    Commercial film processor do not dump chemicals in the drains, they collect them in big drums and then recover silver from chemicals.

  • Ajit Singh Birdi

    When loading the reel, feel which way the film curves and the inside of the curve is the emulsion side any way it does not matter which way the emulsion is when processing in a tank, butt it is better to go with the curve of the cilm.

  • Becca Gulliver

    Thanks and that is obvious when dealing with roll film. Although I didn’t specify in my question, I was actually asking about 4×5 sheet film.

  • film photo

    This is a great article. I have a film camera (canon eos 1v 45mm) and have been on the fence for years considering DIY home processing but never took the plunge.The real roadblock for the younger film photographer is scanning and foremost finding and acquiring a scanner. It’s about the most difficult quest by far. I have studied all CCD and drum scanners offerings on auctions sales for years and it feels like doing technological history research with most units at the peak of that era developped in the 1980-1990s, very outdated SCSI computer interface, OS, floppy disks, parts nowhere to be found, bulbs. Often having to buy an old computer running a prehistoric OS on it to be able to interface with the scanner. And the prices are not low at all if anything the scarcity of complete functionning systems means they sell for thousands $$$$..

    And that really is the problem with film. Nikon Coolscan CCD scanners seems the best bet, but it’s slow and very expensive for something sold as is.

    If you look at the cost of commercial film processing + CD scanning, the processing part is only $5-$7 dollars while scanning + CD is like $15-$20 on top and that’s for erratic quality. If you want drum scanning, it’s $50 per 4×5 slide and up from there, forget it. There currently is no company still manufacturing professional quality drum scanner under $1,000 or even $2000. The only drum scanner company still “in business” entry model is priced at $16,000 pretty much made to order, single unit manual production.
    It is very obvious that had digital photography not eclipsed film then today’s technology would have given us drum scanners on a very large production scale with all the compactness and evolution that comes with it at a mass produced price.
    As much as i love my film camera, sourcing a scanner is a massive problem for any young person. Without dependable scanners available and in production , film can’t survive to the next generation.