I’ve been developing my own film now for over ten years, using Paterson system tanks and reels.

The process of finishing a roll, getting out the dark bag and getting the film onto the Paterson spool has become almost second nature and, when all goes well, almost meditative.

A few moments of calm.

Does it always go well? Ah, no. On those occasions, loading the reel is frustrating, listening to it crinkle and warp, skip out of the tracks. Then your hands start to sweat and you’ve got fingerprints all over your film.

This has happened to me on more occasions than I care to admit and I’m sure most photographers have dealt with the same issues.

I’ve been keeping an eye on the ars-imago LAB-BOX for quite a while, thinking it may be the solution to my issues and then, by chance… I spotted the original daylight processing tank, the Agfa Rondinax 35U, and, surprisingly, for something of a steal.

What are the benefits of using one of these tanks?

First, there’s no faffing about in the dark. As long as you’ve got the film leader out, you just trim it, attach the strap to the end of the film, and put the top on. After that, you wind a knob that pulls the film out from the canister and into the tracks on the reel.

Once you hit resistance, there’s an integrated blade to slice the film so the last of it can be spooled onto the reel.

Second, and in my opinion, the most important, is the volume of chemicals required. In a standard single reel Paterson tank the requirement is 300ml, whereas the Rondinax cuts that by a third to just 200ml. The trade-off for this, however, is that the film needs to be constantly agitated using the knob on the side, constantly rolling the film through the developer.

So what is the Agfa Rondinax 35U like to use?

Well, the first minor issue I encountered was that the clip that clamps onto the film and pulls it onto the reel wasn’t quite as strong as I thought, which meant that as I was trying to load the film, the clip came loose. Not a real problem in my case since very little of the film had been pulled from the canister, but if it did that once say half of it had been loaded, the only way to rescue it would be to put the whole thing into a dark bag.

A decent squeeze of the clip onto the film and it felt a bit more secure, so I carried on, and it loaded properly with no issue.

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The film cutter is easy to use and, surprisingly quite satisfying, giving a recognisable sound that clearly says “The film has been cut” and you can wind the last of the film onto the reel.

The process of developing was simple; pour the developer (slowly!) into the little trough on the top and keep the knob on the side of the unit turning — one half turn every 2 seconds. This works fine and is really easy to do, though I did encounter something of a leak from the hole that the knob fixes into, possibly indicating 200ml is actually a little too much.

At the end of the development time, it’s a case of simply pouring out the developer through the same trough you added it in via, replacing it with a stop or water bath, and then repeating the process for the fixer step. The leak from the hole continued to be an issue for me, particularly when emptying the tank (as it’s on the same side as the little pouring spout), so getting rid of the chemicals without it leaking even more was a bit of a task.

Washing the film is probably the part I disliked most — the manual suggests filling the tank with water, letting it sit for five minutes and emptying it, repeating this process a few times. There are two issues I could see with this method, one of which being the hole for the crank knob. The other problem which is potentially more serious, is avoiding getting water in the slot for the cutting blade or into the little area that the film canister sits in. If this happens, it’s going to take a bit of surgery to take bits off and dry them to stop the blade from getting rusty.

In the end, I removed the reel and washed it separately, which worked fine.

The reel itself doesn’t come apart, so the film needs to be peeled from it which I’ve never done before but doesn’t seem to have had any ill effects on the film.

Agfa Rondinax 35U pros

  • No need to use a dark bag. If all goes well, the entire process is completed in normal light
  • No fingerprints. The only part of the film you touch is the leader when clipping it in and the other end when removing it from the reel, though even that could be avoided.
  • Less chemical usage. Only 200ml per roll per chemical.
  • The frame counter on the side allows you to use part of a roll and develop just that part, leaving the remainder of the roll available to use.

Agfa Rondinax 35U cons

  • Constant agitation is required throughout the entire process.
  • Film leaders need to be left out. No big issue if you rewind by hand, but electronic cameras may not have the option to leave the leader out, meaning you’ll have to retrieve it to use this tank.
  • Leaks. This may be individual to my tank, but its still something to bear in mind.
  • Wear and tear. These tanks have been around a long time now and, as with all things, will have worn components. In my case, its a slightly loose clip and frayed ribbon attaching it to the reel.

To summarise

I did enjoy using the Rondinax, though it isn’t without its issues. Washing the film is probably my biggest bugbear, followed by the leak, and it should be understood that while it can be an easier method of getting your film developed. If something goes wrong with the loading, you’re in no better position than with a normal Paterson spiral.

The other thing to note is that, while the volume of chemicals required is much lower than a single reel Paterson, the number of cylinders/jugs required to store them is not. You’ll still end up with the same number of things to wash as if you’d used a Paterson tank in the first place, albeit potentially smaller ones.

Am I glad I bought the tank? Yes, absolutely. Would I buy another? Probably, if it was the right price. The extra convenience isn’t worth the massive costs that some of these units are going for. Once it reaches a certain price point, you’re probably better off buying a LAB-BOX, which could well be a very good and easyish way for beginners to get into developing their own film.

~ Mads

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About the author

Avatar - Madison Steinberg

Madison Steinberg

I’m a forty-ish amateur photographer in the southwest UK. I’ve a soft spot for the Olympus Trip, it being the first camera I remember using and getting a decent photo from (a sunrise photo, which I still have a thing for taking) I came back to film...


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  1. I use the Johnson’s of Hendon produced, British patented, Essex 35 and Kent 20 tanks for 35mm and 120 film respectively. These were a limited production run produced only from 1952 to 1954 and are virtually a copy of the Rondinax equivalents, with one major difference, the plastic is thicker and stronger.

    They were produced as the Agfa products were embargoed at the time and in 1954 when the embargo was lifted the Johnson tanks faded away.

    I have had the Essex tank since I was 10 and it has been in use continually since, I bought a Rondinax 60 to process 120 film a few years ago – a total failure as it mangled every film put in it, I replaced it wit a Kent 20 tank which has performed faultlessly ever since purchase despite being at least 65 years old. The only repairs I have made is to replace the canvas strap on the Essex about 6 months ago.

    This is the easiest method of processing 120 and 35mm film, but for colour films I have to resort to a Jobo CPE as it has the necessary temperature control, albeit harder and more inconvenient to load.

    I would be interested to know if anyone has used a Rondinax, Johnson or Lab Box to process colour film and how they maintained the necessary temperature control

  2. What a great article – thank you for sharing your insights. I was almost tempted to buy one of these a few years ago but for whatever reason it didn’t really seem to make life easier, so I just stuck with the Paterson reels. And it must be said – your Kentmere 100 photos are easily the best I’ve seen. I always found examples of this emulsion to be very gritty but your images are smoothly beautiful.

  3. Absolutely fool proof way to load a Paterson reel. I can’t believe Patterson does not include this little device with every tank they sell. Cut a piece of plastic that is 1 1/2“ x 3 1/2“ long. A little bit thinner than a normal credit card. I used an old AARP card. Put a slight point on one side. Use a toenail clipper to kind of smooth out the cuts. In complete daylight slip the card into the slots of the reel at the entrance Point where the little knobs are ahead of the ball bearings. The little piece of plastic is the landing strip for the film. I use a changing bag and put this along with all the other items the can opener the scissors etc. in a small plastic container keeps everything where are you need it. Once you’re in the dark bag and get the film started you then pull the little piece of plastic out and feed the film into the reel as normal. I develop my film using the Patterson swizzle stick and decided not to do the inversion method just too messy. A tip using a swizzle stick is to make sure that you rotate in a clockwise fashion and that the reel is catching the liquid as you turn the swizzle stick. You’ll need one of the little pieces of plastic for every reel you put in your tank. Like always practice this procedure in daylight just to get the hang of it and Paul the piece of plastic out always from the Same side. Before I load film I wash my hands with dish soap with cool water and that sure helps a lot with fingerprints hope this helps

  4. Yes it does. The problem is that the plastic crank accessory (v. Expensive) is not held on by anything except friction. It just comes off during rotation.

    1. Thats less than ideal. Surely a screw hole would’ve been easy for them to implement?

      1. The assembly turns to “lock” in place but it just turns while agitation is in progress and pops out. This can be avoided but I will possibly use gaffer tape to hold it in place. This is an expensive piece of kit and this should not even stand a chance of happening.

  5. I have a Rondinax 35U and a Lab-box. One extra advantage of either of them: because of continuous rotation, your dev times should be reduced by 15%, to 85% of the normal times!

    A few warnings on the Rondinax: do load the film in subdued light. I started loading it in the laundry with strong side light, and sufficient was reflecting from the counter top up the guillotine slot to cause light leak artefacts where the film paused while winding it in! Secondly, do remember to lower the guillotine before loading a film, as it can cut the film when the tension increases (mine doesn’t just drop back, I have to push it back with the lever). Thirdly, watch out for films with a polyester base like Rollei Retro; my guillotine wouldn’t cut it, had to hide under the stairs to open it and cut with scissors! Oh and fourthly, bend the corners of your trimmed film leader inwards a bit, which helps it stay on the reel.

    I also find it easier to attach the film to the strap before dropping the canister into its slot. You let the strap dangle over the opposite side of the tank, then hold the canister the other way up, and attach it, making sure the teeth have got a good grip, before lifting the canister up and into its slot and winding the leader in a bit.

    These tanks are getting on a bit, which can be a problem. On mine the two leaf springs that make sure the lid stays on tightly have broken. I just use a rubber band over the top, and also make sure I hold the top while dumping the chems.

    The Lab-box takes 300 ml, so for that and other reasons, I don’t use it for 135 film. However, I do have the 120 module, and I’ve done a couple of 120 films that way. I find it a little harder to load the chems in the Lab-box; the tray areas seems shallower and there was more wastage. It’s also lighter, which sounds like a good thing, but I found I had to hold it with one hand while turning with the other. I did buy a handle, but gave up on that and reverted to the knob; the handle gets a bit too close to the surface for comfort, and I also felt there was a tendency to always pause the rotation in pretty much the same place, which could lead to uneven development (with the knob, any pauses are in more random places, so effects would not build up).

    However, these two tanks have allowed me to develop film where I would otherwise not be able to, because limited use of one hand due to injury would make loading a reel impossible.

  6. I also have the Lab Box which is clearly a straight copy. It lashed up my first 5 films because the nibs from the moulding sprues made the spool sides run eccentric which meant the film would only stay in spool at one position in the feed and slip out of the groove in the opposite side. I have identified this problem and trimmed off the “nibs” It appears to run true now but I haven’t tested it. There was also the problem of the knob coming out and dumping developer all over the kitchen floor!

    1. Interesting, do the chemicals come up much higher than the hole for the turning knob? I found on the Rondinax that it comes up to the hole, and its the agitation that pushes some out of the hole.

  7. Aaaah, your review brings it all back …
    The Rondinax 35U is the device I started off with in the 1960s, when I was 12, and my first film had to be developed. That unit is still with me, but was sent into retirement in the early 1980s when I upgraded to JOBO tanks, which I have been using ever since. I also have a 120 model for medium format films. The main problems I encountered with both tanks were problems relating to film not properly winding onto the spool and as a result parts of the film sticking together and ruining the frames that weren’t exposed to the developer/fixer.
    About two of your concerns:
    – The problem regarding those pesky leaks around the winding knob might be resolved if you tightened the pressure of the holding screw a little by adding a thin washer between screw and knob. Also, a very thin film of vaseline should restore the thick rubber washer to some of its former glory, improving its water-blocking capabilities.
    – I wouldn’t worry too much about water entering the film compartment and the slot with the cutter. I have just checked mine: there is absolutely no rust on any of these parts, although I regularly flooded the whole tank during the washing process after fixing the film.
    Best of luck with your vintage Rondinax,
    Jens in Germany

    1. Thanks for your comment Jens.
      I’ve not had any issues with the film misloading so far, but I suppose its just one of those things that eventually we encounter, just like jams on a patterson reel.
      I’ve tried using film aprons before and found I had them too tight, so I had great swathes of film completely undeveloped, but thats a story for another post.

  8. Thanks for this article, excellent. I have this Rondinax 35mm tank and really like it. I like the way I can sit on the sofa watching TV while I develop films! It does leak a little at the winder hole, but no big deal.
    However, the 120 version (called the Rondinax 60) can be a bit of a nightmare! The fundamental problem is 120 backing paper – there is no easy way to separate the paper from the film. The Rondinax 120’s method sometimes works and sometimes wrecks the film. It’s about 50/50. So in the end I decided that, for me, the 35mm version is worth having and the 120 version is not worth having.

    1. Thanks Ray, I really appreciate that.

      I must admit I’ve been looking at the Rondinax 60, but they are silly money. Its a shame, especially since the 60 uses even less chemicals than the 35.

    2. Hmmm, with the Rondinax 60 I’ve never had a problem separating the film from the backing paper, BUT with winding the film onto the spool without parts of the film stickig together and ruining the affected frames during development. But then again: this occurrred only in perhaps 5% of films developed. So not really so much of a big deal.

  9. My preferred daylight loading tank is/was the Jobo 2400, which for me had two distinct advantages – it used inversion agititation which was my preferred technique, and the film cutter could be used to cut the film so that short sections of film could be developed, leaving the unexposed remaining film in the cassette for reloading in the camera. The only downside is it uses 450ml of developer for one 36 exposure film, and this translates into a lot of developer, say, for a short section of film!

    I haven’t used it for a while, and I’ve been somewhat shocked at the prices being asked for one of these today.

    1. I’ve got one of those, but I could never get the cannister to eject once the film is cut.
      One of the things I really like about the Rondinax is that you can do the same thing with only loading some of the film to use the rest at another time.

  10. I have used the worthy Paterson tank for the last ten years, but if I’m looking at a 35mm cassette, I turn to the FR model 2 tank that I acquired in 1960. What is the difference? Simple. The FR has a pointed hook on the reel’s spindle. If I anchor the film on it and then cup the film as I roll it on, nothing can go astray. By contrast, the Paterson frequently fights back. I reserve it for 120 film.

  11. I have the LabBox and used with for my first film developements (both 120 and 135) and all went well. I also have a Rondinax 35 but the rubber part that holds the thermometer died of old age and leaked. I tried to get on but looked in the wrong places, a shop that sells car repair parts would be the one to go to, getting one of those protectors for cabple that go through holes in the car’s body. Thanks for sharing your experiences!
    Best regards
    Martin in Austria

    1. Thanks Martin, I’ll have a look for some of those rubber O-rings.
      I did think it’d be very similar to the LabBox, but don’t have one to do a straight test against.