Midtone Machines - Automatic Film Processing Machine

[AndrewBurns]

Hi all, I'm an engineer from New Zealand who is also a (recent) keen film photographer, starting with 35mm and moving up to a lovely Chamonix 4x5 field camera.

I've done a fair bit of home film development of various kinds and have spent some time talking to local photographers and small film lab owners. As a result of this I've decided to kick off a project to build and eventually market a new fully automatic film processing machine targeted at the hobby/light commercial market.

As part of this effort I've put together a quick website where I'll be posting regular updates of the progress of this project, and hopefully getting people interested and commenting/discussing so that we all end up with the best possible result.

So if this sounds like something that would interest you, the website is http://midtonemachines.com

Please go have a look, and subscribe/comment/share on social media if you'd like. I also intend to post updates into this thread as I go as well.

[Peter De Smidt]

Good luck with the project!

[Tin Can]

Yes, good luck!

Many here shoot only sheet film.

For some this forum is the only social media.

I signed on for updates.

[Oren Grad]

Good luck, Andrew! To make sure that your efforts are well-targeted and that the feedback you get is informative and realistic, it will be helpful for you to explain in what ways, if any, you expect your device to differ functionally from alternatives currently available new - Jobo CPP3, Stark SST4/SST8, Filmomat, Heiland TAS - and roughly what price level you will be targeting.

[AndrewBurns]

Thanks for the comments so far, yes my next blog post will be coming in a few days (about to go on holiday for a few days so not much time to reply right now) and I'll hope to cover what the existing market/options are, what I've done to determine where the need is, what my plans and point of difference are and how I intend to go from here.

[AndrewBurns]

New blog post/update hopefully with some answers to questions people have:

On the Shoulders of Giants (http://midtonemachines.com/news/on-the-shoulders-of-giants/)

Now for a large format specific question. Personally the only sheet film I shoot is 4x5 and only very recently. One of the things I really want this machine to do well is sheet film (specifically so I can process my own E-6, I don't think there's really anywhere in my country still doing E-6 sheet film processing). Can people link me to as many examples of rotary processing machine sheet film holders they know about? And if anybody has personal experience I'd love to know what works well about them and what doesn't. The more I know the better the chance that whatever I end up making will work!

[ic-racer]

How do you clean it after use? I'd think that would be the one thing were improvement over existing film processors could be achieved. In a "Lift" Jobo, each bottle needs to be rinsed with water after use, and 1 liter of water needs to be poured through the lift. With the Jobo, this additional step adds 30 seconds to my day. Can your device improve on that?

[Tin Can]

Good ideas!

I don't consider chemistry volumes a big deal. Dilution is good.

Are you sure you have considered all users and methods extant?

Some still shoot 8 and 16mm movie film. I don't. I did.

I use several ways to process sheet film.

The easiest is 2-1/4 X 3-1/4 inserted in a NIKOR 'waffle' hand inverted in a 120 tank. Up to 12 sheets. They even dry in the waffle. Perfectly processed. Daylight. See pic below.

I have Calumet Gas Burst SS tanks with a DIY regulator and timer. Hangers. 4 liters does up to 16-4x5, 8-5x7 and 4-8x10. Also Daylight with double light trap lids. Peaceful. You tube video. (https://youtu.be/9DddOzSUeRc)

11X14 is done one at time in open trays. Considering price of 11X14 film I am in no hurry. Sometimes X-Ray film under safelight.

I use a 4X5 NIKOR spiral rarely. But it does adjust to 3-1/4 X 4-1/4. I just ordered 200 sheets from China.

NOS NIKOR 2X3, I have 3 sets. In the right rear is a much older system that may have been for pack film. IDK

https://live.staticflickr.com/65535/48280548022_94e3385b08_b.jpg (https://flic.kr/p/2gyoqRL)1-90-2x3 sheet film waffle (https://flic.kr/p/2gyoqRL) by TIN CAN COLLEGE (https://www.flickr.com/photos/tincancollege/), on Flickr

[Peter De Smidt]

Jobo Expert drums.

[AndrewBurns]

Thanks for the replies so far, keep 'em coming.


How do you clean it after use? I'd think that would be the one thing were improvement over existing film processors could be achieved. In a "Lift" Jobo, each bottle needs to be rinsed with water after use, and 1 liter of water needs to be poured through the lift. With the Jobo, this additional step adds 30 seconds to my day. Can your device improve on that?

One of the inputs to the machine would be water for rinsing/flushing (tap or deionised water depending on you preference). After the process is complete the machine would automatically clean itself by flushing water through the dev tank and pump. It's designed to suck in chemistry from whatever bulk container you'd like which wouldn't ordinarily require flushing after each use however if you wanted to change chemicals around there will be a full cleaning cycle that would flush water through all channels. All of these features would of course be fully automatic so you wouldn't need to do anything, just come back when it's finished.

[Oren Grad]

How do you clean it after use? I'd think that would be the one thing were improvement over existing film processors could be achieved. In a "Lift" Jobo, each bottle needs to be rinsed with water after use, and 1 liter of water needs to be poured through the lift. With the Jobo, this additional step adds 30 seconds to my day. Can your device improve on that?

To be clear to those who are not familiar with the Jobo processors, the processor needs an after-wash only if you don't do the film wash on the processor. If you do, that takes care of both the film and the processor. (The bottles do get a brief rinse as part of my clean-up afterward.) If for some reason one couldn't conveniently do the wash on the processor, that would be a strike against it for my purposes.

Getting back to Andrew's additional question, I use the Jobo Expert drums. A key benefit of the Jobo drum system for some of us is the ability to accommodate a wide range of sheet film sizes other than 4x5, from 2.25x3.25 all the way to 20x24. That said, I think it's likely that 4x5-only users are the largest subgroup within this small market.

[AndrewBurns]

Do the JOBO expert drums show any issues with chemistry not getting to the back of the film? I've used the 'taco method' for developing my 4x5 sheet film with a hair band to hold the film and there was a mark where the band was touching the back of the negative and the anti-halation layer didn't go away (it wasn't noticeable in the scan at least). I do like the 'mail tube' idea of holding film, specifically because it can hold a wide variety of film sheet sizes without modification.

[Peter De Smidt]

Nope. No issue with film back. The drums are designed to allow solution to reach the back.

[Oren Grad]

What Peter said. A key point about the 3004/3005/3006/3010 drums is that the "wells" in which the film is inserted are not strictly cylinders - they are slightly barrel-shaped. The structure of those drums is actually quite complex - the housing is hollow and has slots to allow water from the processor's tempering bath to enter and create an internal water jacket to further facilitate temperature control. The complex construction is part of why they are so expensive, but also an important part of why they work so well.

See also this thread:

https://www.largeformatphotography.info/forum/showthread.php?117695-Homemade-Jobo-3005

A pure cylinder shape can work well for develop/stop/fix of the emulsion, but it will often mean that the film requires separate clearing and wash steps outside of the processor after that.

The big 3062 and 3063 drums are just overgrown print drums, hollow shells with ribs molded into the internal surfaces of the shell to allow fluid behind the sheets. These have worked well for me in developing ultra-large sheet film sizes with standard metol- or phenidone-based developers, but the ribs have been reported by some to cause artifacts when pyro developers are used.

[AndrewBurns]

New blog post up, details of a survey I put out a month or two ago:

http://midtonemachines.com/news/a-slice-of-pie-charts/

There's also a link at the bottom of the past to the survey if you want to make your thoughts heard. I developed two sheets of 4x5 Ektar using the taco method this morning, development went fine and the negatives look good but the hair bands came off inside the tank at some point and I got quite a few scratches. I'm making sure I have constant incentives to move this project along!

[ic-racer]

Thanks for the replies so far, keep 'em coming.



One of the inputs to the machine would be water for rinsing/flushing (tap or deionised water depending on you preference). After the process is complete the machine would automatically clean itself by flushing water through the dev tank and pump. It's designed to suck in chemistry from whatever bulk container you'd like which wouldn't ordinarily require flushing after each use however if you wanted to change chemicals around there will be a full cleaning cycle that would flush water through all channels. All of these features would of course be fully automatic so you wouldn't need to do anything, just come back when it's finished.

That would be great. I was just using my Jobo last evening and I can't see doing it without the darkroom sink and tempered/filtered water to prepare each bottle of chemistry, then to rinse each bottle and graduate for the next use. For example, rinse bottle, rinse graduate, add concentrate to graduate, dilute with filtered water from the darkroom sink, rinse graduate, repeat with next bottle, etc. If somehow yours could automatically dilute the concentrate solutions too, that would really make it 'plug and play.' The important thing being dilute solutions won't last, so the machine needs to be in constant use like almost every commercial machine already in existance, whereas the concentrated solutions last years.

As I think about this I realize my wife's clothes washer has the ability to accept powder or concentrate. It automatically dilutes either one. That is another interesting idea, that your machine could dilute a powder too!

[Tin Can]

Have you studied X-Ray processors both for transport, dilution baths and concentrate bottles?

https://www.largeformatphotography.info/forum/showthread.php?153314-Fast-X-Ray-Film-Processing&p=1509409&viewfull=1#post1509409

[AndrewBurns]

That would be great. I was just using my Jobo last evening and I can't see doing it without the darkroom sink and tempered/filtered water to prepare each bottle of chemistry, then to rinse each bottle and graduate for the next use. For example, rinse bottle, rinse graduate, add concentrate to graduate, dilute with filtered water from the darkroom sink, rinse graduate, repeat with next bottle, etc. If somehow yours could automatically dilute the concentrate solutions too, that would really make it 'plug and play.' The important thing being dilute solutions won't last, so the machine needs to be in constant use like almost every commercial machine already in existance, whereas the concentrated solutions last years.

As I think about this I realize my wife's clothes washer has the ability to accept powder or concentrate. It automatically dilutes either one. That is another interesting idea, that your machine could dilute a powder too!

Can your washing machine dilute from any quantity of powder/concentrate or do you have to add the right amount for every load? Currently the machine doesn't have the capability to mix solution internally (it wouldn't have the accuracy required) however I know exactly how you could do it and I could imagine it being an optional add-on potentially. Basically it would require a small preistaltic pump inside the machine with an encoder for concentrate, that way the machine would know exactly how much volume of concentrate it had pumped and could make up a mixture with water of any reasonable concentration.



Have you studied X-Ray processors both for transport, dilution baths and concentrate bottles?

https://www.largeformatphotography.info/forum/showthread.php?153314-Fast-X-Ray-Film-Processing&p=1509409&viewfull=1#post1509409

I haven't really looked into x-ray film machines, I would imagine they're generally larger roller transport machines?

[Tin Can]

OP, your job is research.

[AndrewBurns]

New blog post is up:

http://midtonemachines.com/news/meat-and-potatoes-fluid-diagram/

This time I've shared the fluidic system diagram and gone into some detail about how the chemicals move around the machine. I've been getting lots of prototype parts in over the last few weeks and I'm close to 3D printing the development tank components so I can do fit and functional checks before committing to vacuum resin casting a batch of 10.

[Jim Noel]

Do the JOBO expert drums show any issues with chemistry not getting to the back of the film? I've used the 'taco method' for developing my 4x5 sheet film with a hair band to hold the film and there was a mark where the band was touching the back of the negative and the anti-halation layer didn't go away (it wasn't noticeable in the scan at least). I do like the 'mail tube' idea of holding film, specifically because it can hold a wide variety of film sheet sizes without modification.

Jobo drums are not cylinders. They are barel shaped so there is little if any contact between the back of the film and the drum.

[AndrewBurns]

Pretty clever, and definitely something I could imagine making work in the machine.

Maybe of interest I got a quote from the only place I'm aware of in my country (New Zealand) that processes E-6 sheet film and they want $17 NZD per sheet of 4x5 processed...

Also currently getting quote for 3D printing some prototype components and received a shipment of sample power supplies today, things moving along at pace.

[Tin Can]

Jim,

Now that barrel shape impresses me.

I have not heard of that before.

Perhaps I will try one of these very expensive plastic cans.

Thank you!


Jobo drums are not cylinders. They are barel shaped so there is little if any contact between the back of the film and the drum.

[AndrewBurns]

New post, this time with detail of the developing tank design.

http://midtonemachines.com/news/the-develop-tank/

I've also included a shot of some parts I've ordered in for prototyping and I have some 3D printed developing tank pieces on the way for doing fit and functional checks before getting the final versions made.

[Peter De Smidt]

Great work! I've never seen a tank with a horizontal seam like that. Making it leak proof won't be a challenge?

[Two23]

I've been doing fine processing B&W with my Patterson tank and SP-445. However, if I read it right you're designing your machine to do C-41? If so, yes I'm interested. Mostly 4x5 but also 35mm and 120.


Kent in SD

[AndrewBurns]

Great work! I've never seen a tank with a horizontal seam like that. Making it leak proof won't be a challenge?

Peter, the now discontinued Phototherm used a very similar tank and I can see why after going through the design process myself. Because the liquid level never gets above just under half-way up the tank the seam and spindle pass-through only need to be light-tight and not water tight. The JOBO design means there's no seam but because the entire tank rotates you can only get chemicals in and out through the middle of the tank, which means you need a lifting mechanism as well which this design doesn't.


I've been doing fine processing B&W with my Patterson tank and SP-445. However, if I read it right you're designing your machine to do C-41? If so, yes I'm interested. Mostly 4x5 but also 35mm and 120.


Kent in SD

Kent, yep this will be capable of doing everything, C-41, E-6, B&W, either with standard pre-set programs or whatever you want to program in (I plan for a large touch screen and some buttons as the interface). Personally I really want it for doing 4x5 E-6 film but I also shoot a lot of 4x5 Ektar and 35mm of all types.

[Peter De Smidt]

Peter, the now discontinued Phototherm used a very similar tank and I can see why after going through the design process myself. Because the liquid level never gets above just under half-way up the tank the seam and spindle pass-through only need to be light-tight and not water tight. The JOBO design means there's no seam but because the entire tank rotates you can only get chemicals in and out through the middle of the tank, which means you need a lifting mechanism as well which this design doesn't.

Got it. Neat!

[calebarchie]

Hi there, cool project just like an updated Phototherm, I am not sure if the hairdryer is used to maintain temp or just drying?

I have also played around with silicone heaters on tanks metal and thermoset plastics, I am not sure how they would fare with thermoformed 3D printed plastics after a while. Something you may need to design for, or perhaps have a stainless steel element sealed on the bottom (I have done this for my nova clones)

Otherwise, why not make use of spindle for temperature maintenance (although close to film) which brings me to another question; the chemicals will be preheated before coming into the tank correct?

[AndrewBurns]

Yes the bulk of the heating is done using an immersion heater in a separate tank prior to pumping into the development tank, heating the development tank is just required to prevent the chemicals cooling down over the few minutes they're in there. The final tanks will likely be made from a polyurethane compound using vacuum resin casting (I don't think production volumes will be high enough to justify injection molding) which has a heat deflection temperature around 72 degrees Celsius. Realistic film developing process temperatures will be more like 40 degrees C so I don't think there will be a problem with deformation, but if there is during development I might have to look into more heat resistant plastics.

As I mentioned in the blog I'd rather not have any kind of electrical contacts on the developing tank because they're sure to get unreliable eventually given that the tank is being connected and disconnected every cycle. This means that any temperature maintenance has to happen from the outside of the tank.

[calebarchie]

That is fair enough - I was going to ask what kind of volume production you were expecting. I have used heat resistant epoxy-resins from Smooth on (Epoxacast HT) there is a good store there in NZ too can't recall name.

Just note that the temperature would still need to be a bit higher than process temperature but if you are preheating then it should be OK. I have used the pads to heat up a Bakelite rondinax from room temperature it needed to get up to 90degC to reach around 38 internally - at that point the plastic was starting to gas and sustain some surface marring.

The contacts themselves serve other purposes such as tank identification for process selection/amount of rolls etc so you may need to design around fail-safe processing prevent over/under filling etc. If casting embedding a stainless pad on the underside of the tank should be quite easy to achieve so perhaps give it a try? That resin is quite expensive I was only using it for small machinable parts, entire tanks this size will be $$$, if you use a pad you could get away with lesser resins methinks. The pad itself would not have to not have to share any electrical signal, just be a transfer heating element say from a silicone heater.

Just food for thought, good luck with it.

[AndrewBurns]

I got a few quotes for representative parts in the early days both for vacuum resin casting and injection molding (offshore manufacturers). The cross-over point where injection molding made sense when including tooling costs was about 350 parts. Of course another difference is the injection mold tooling cost up-front is massive (probably would have been well over $100k for this project) while the vacuum resin cast tool cost is split over every ~10 parts, so there's much less risk and capital investment required up-front.

That said if there ends up being a lot of interest I could potentially go injection molding which could potentially bring the cost down a bit.

I can see how having to heat the outside of the tank to actually get significant heat transfer into the liquid would require quite a high temperature, but in this case I'm effectively stopping heat transfer out of the tank by maintaining the outside of the tank at a slightly higher temperature than the liquid. As for knowing what tank is fitted that's a good point, I might potentially be able to do that with some non-contact method (maybe a magnet) to tell the machine if a 4 or 6 roll tank has been inserted. If there is an overflow it will get caught by a spill tray at least.

[calebarchie]

Sorry I meant the external heating pads on the tank will still need to be well over process temperature = poor transfer coefficient through the drum. Unless you preheat the drum itself or have more heating surface area (eg wrap it around the whole tank) Would just have to test and try it wouldn't drop that much anyway.

The main thing is if you don't want any contacts on the drum is it going to be a mostly open loop system? Or figure a way to get around that.

[AndrewBurns]

The heating pad under the drum will be closed-loop controlled, I'll probably have to do some experimentation to work out how much higher than the process temperature it will have to be to account for heat loss and poor heat transfer through the plastic. The heating of the fluid in the develop tank will be essentially open loop in that the exact temperature of the fluid won't be measured but the temperature of the outside of the tank will be measured and controlled. I imagine I'll have to control this to a few degrees higher than the desired process temperature to maintain correct fluid temperature once losses are taken into account.

The heating of the chemicals prior to going into the develop tank will however be fully closed loop as both the heater and the temperature sensor will be immersed in the fluid, so the develop tank heater only has to maintain the correct temperature for a few minutes, not get it there in the first place.

All of that said and done, if during testing I find that I can't keep adequate temperature control of the fluid in the develop tank during the process then I can always add in a sensor to close that loop, I just think that I can avoid it which has definite benefits to cost and reliability.

[Oren Grad]

In rotating the spindle, do you have any provision for avoiding standing flow patterns? The obvious one would be periodically reversing the spin, but even that needs testing with respect to different chemical processes, reversing intervals, and core-and-reel configurations to assure that it's effective.

[AndrewBurns]

In rotating the spindle, do you have any provision for avoiding standing flow patterns? The obvious one would be periodically reversing the spin, but even that needs testing with respect to different chemical processes, reversing intervals, and core-and-reel configurations to assure that it's effective.

Yes the plan is to periodically reverse the direction of rotation, there is also quite a bit of axial clearance for the spindle which will result in some displacement during agitation. I'm not convinced yet that I'll need to do anything more as I think the environment inside the tank will already be quite turbulent but if I found that I had to do something during testing there's plenty of scope for that.

[calebarchie]

I just think that I can avoid it which has definite benefits to cost and reliability.

I really wouldn't worry too much, I think the problem with the Phototherms was that the control and SW was so rudimentary with no overrides or fail-safes (say if the tank couldn't be identified via magnets or probe failed due to too much resistance). The SS models worked towards this and improved flexibility with custom programs etc but still used the same hardware.

[Duolab123]

I would be very concerned about all the valves. Seals going bad etc.

[AndrewBurns]

I would be very concerned about all the valves. Seals going bad etc.

For a variety of reasons I'm currently going to use pinch valves, essentially the valve is a section of silicone tube that is squished to prevent flow. It's a fairly common technique in medical/chemical applications where pressures are very low and chemical compatibility and a lack of trapped volume or places where contamination can collect is important.

I feel they're good for this application for the following reasons:

- Based on the design I need a valve that positively blocks flow in both directions, common direct acting solenoid valves tend to only really block flow in one direction and will pop open when pressurised in the reverse direction, which I can't have in this case
- Pinch valves are quite simple and there is no material exposed to the process fluid other than the tube material
- They don't trap any fluid volume or present any cavities where deposits could form, which is good for minimising potential chemical contamination

The tube itself should be good for several hundred thousand cycles (potentially ~ 1 million rolls of film) and replacement should be easy and cheap.

[Peter De Smidt]

Peristaltic pumps? I used them with salt-water aquariums for years. The maintenance boils down to replacing the tubing every few years.

[Duolab123]

For a variety of reasons I'm currently going to use pinch valves, essentially the valve is a section of silicone tube that is squished to prevent flow. It's a fairly common technique in medical/chemical applications where pressures are very low and chemical compatibility and a lack of trapped volume or places where contamination can collect is important.

I feel they're good for this application for the following reasons:

- Based on the design I need a valve that positively blocks flow in both directions, common direct acting solenoid valves tend to only really block flow in one direction and will pop open when pressurised in the reverse direction, which I can't have in this case
- Pinch valves are quite simple and there is no material exposed to the process fluid other than the tube material
- They don't trap any fluid volume or present any cavities where deposits could form, which is good for minimising potential chemical contamination

The tube itself should be good for several hundred thousand cycles (potentially ~ 1 million rolls of film) and replacement should be easy and cheap.

That's a good idea. Silicone should work well with dilute photo chemicals. I would double check it with E6 color developer. Decades ago, when I was a analytical chemist I tried to transfer cool 35% NaOH with Silicone tubing. Very dumb. :rolleyes:

[Duolab123]

Here's a possibility dumb idea. Could you transfer chemistry by gravity. To use "cock" the tanks in a up position, manually. After dispensing, trigger a latch that would drop the chemistry bottle below the developing tank.
The chemistry could syphon in and out pretty quickly????

Another point from working in a laboratory with silicone tubing, be careful of pressure. The tubing gets slippery.

[AndrewBurns]

Peristaltic pumps? I used them with salt-water aquariums for years. The maintenance boils down to replacing the tubing every few years.

Same principal as peristaltic pumps except just closing or opening the tube rather than pumping liquid. Not using peristaltic pumps for the actual pump part of the machine because they're not commonly available with a flow rate as high as I'd like (the slower the fluid transfer into/out of the develop tank the higher the possibility of uneven development).


That's a good idea. Silicone should work well with dilute photo chemicals. I would double check it with E6 color developer. Decades ago, when I was a analytical chemist I tried to transfer cool 35% NaOH with Silicone tubing. Very dumb. :rolleyes:

Will check it out, but yeah on the whole standard photochemicals are pretty benign.


Here's a possibility dumb idea. Could you transfer chemistry by gravity. To use "cock" the tanks in a up position, manually. After dispensing, trigger a latch that would drop the chemistry bottle below the developing tank.
The chemistry could syphon in and out pretty quickly????

Another point from working in a laboratory with silicone tubing, be careful of pressure. The tubing gets slippery.

Definitely sounds possible but a lot less flexible as a system and probably more complicated and expensive than just using a pump. I know some people want to use chemicals from large bulk containers for example, which is easy if you can pump up from below the machine but you're not going to be swinging large tanks of liquid up and down easily.

Yeah as far as pressure goes although the pump is capable of generating reasonable pressure it should never have to as it's only ever pumping into containers that are vented to atmosphere. It's a good point though, I might have to think of adding a pressure relief valve though in the failure-case where one of the valves has broken and the pump is trying to pump through it.

[Duolab123]

I hope it all works out. I like the idea of using the bottom half of the tank as a "trough" of sorts to spin the reels in. I have a bunch of Jobo stuff, my littlest is my dear little Duolab, it only spins in one direction, but if you're only developing a couple rolls of film it works perfectly well. It's about the size of a old typewriter. The heater is from a Mr. Coffee type pot. Couldn't cost more than a couple bucks.

Something about that size would be great. Paterson reels are great, but make no provision for loading 2 rolls of 120 on one reel, it can be done but it's tricky. For 35mm Paterson are unbeatable.

[AndrewBurns]

New post is up, showing off some 3D printed parts I got for fit-checking the develop tank and a few other parts of the machine:

http://midtonemachines.com/news/3d-printed-goodies/

Everything is fitting together pretty nicely and looks like it should work fine, so some good solid progress!

[Duolab123]

Looks pretty neat. It would be great if the market was big enough to justify injection molding tooling. You could make 10,000 tanks in a week or two. There's so darn much used stuff out there, even the new darkroom products typically use decades old tooling.
Keep going!
Best Regards Mike

[AndrewBurns]

Looks pretty neat. It would be great if the market was big enough to justify injection molding tooling. You could make 10,000 tanks in a week or two. There's so darn much used stuff out there, even the new darkroom products typically use decades old tooling.
Keep going!
Best Regards Mike

Cheers. I got some quotes early on and once you include tooling costs it seems that the cross-over point where injection molding starts to make sense is about 350 parts. Honestly I'm not sure I'll be selling that many machines but who knows, once I have working prototypes I might use Kickstarter to see how much interest there is and if I get enough I might go down that road.

[calebarchie]

Just a thought; since the design of the tank is pretty much identical to the phototherm, perhaps you should also make it compatible? Just retrofit the probes and contacts and sell the same part as a replacement tank?

There would be even more interest and users to justify that volume if you did so. I have a phototherm machine and willing to assist with design and testing if you decide to do so.

[AndrewBurns]

Just a thought; since the design of the tank is pretty much identical to the phototherm, perhaps you should also make it compatible? Just retrofit the probes and contacts and sell the same part as a replacement tank?

There would be even more interest and users to justify that volume if you did so. I have a phototherm machine and willing to assist with design and testing if you decide to do so.

Yeah it's very similar to the Phototherm. I originally wanted to go along a different route but as I was designing I realised that there's a lot of good reasons for it to look that way and if made what I thought were good design choices my tank ended up looking a lot like theirs, so kudos to the Phototherm people I can definitely see why they did what they did.

That said there are a few things about their tank that I'm not too keen on, I don't really like the massive light trap they use for their chemical inlet or the idea of having a temperature sensor inside the tank with electrical contacts or using hot air to maintain tank temperature. If I were to make the tank designs cross-compatible I'd have to compromise on other aspects of my design that I think are important, like size and functionality. We'll see how it goes as I get into live testing over the next few months though, maybe I'll find more reasons to change my design closer to theirs in which case it could end up being something I do, never let it be said that I'm somebody too stubborn to change my mind when it makes sense to do so.

[calebarchie]

Can you elaborate on the light trap? I haven't had any issues.

Your designs look about the same size as a 4-roll tank I mean I don't see how it could be any smaller or larger regardless. Sorry I think you misunderstood, I mean if you make any tooling or molds, have design provisions to allow it to be retrofit for Phototherm compatibility, eg have a spot for the contacts or, but in your version simply omit them. The probes and magnets are very, very basic stuff (infact they just drilled holes into the tank to fit/glued them in) do you need me to take some pictures?

It would be a bit of a shame if if you were to make a tank with such minor changes from the phototherm without considering cross-compatibility, there is a pretty high demand for these things. Others would ask sooner or later, just sayin'.

[Louis Pacilla]

Can you elaborate on the light trap? I haven't had any issues.
It would be a bit of a shame if if you were to make a tank with such minor changes from the phototherm without considering cross-compatibility, there is a pretty high demand for these things. Others would ask sooner or later, just sayin'.

Plus one! Being a Phototherm owner I agree fully. I would be interested in the ability to buy cross compatible parts if needed.

[Duolab123]

Question, is there still tooling for Phototherm tanks? Jobo, thank goodness, had the resources to preserve the tooling. As all the old equipment dies there's going to be significant demand for equipment.

To the OP, design what you want. As long as you aren't using hard tooling changes are easy.

[calebarchie]

Andrew is probably trying to test the prototype about now. Since we haven't heard back, just thought I'd point out some design oversights that may prevent some headaches;

You mentioned you light trap design perhaps it is too bulky? It is like for good reason, the input is below the tank to allow even filling and prevent uneven development. Having the input in-line with the reels in your model may create surge marks or uneven dev phenomena across all the rolls as the tank slowly fills to capacity.

The Phototherm tanks aren't exactly as simple as you may make them out to be. They aren't perfect cylinders there is a slight draft along the length of the tank to assist with drainage but also again to assist with even filling and development. In this case the furthest rolls from the input are closest to the bottom to account for in inlet being on the opposite end. There are ribs on the bottom to keep any leftover chems put until the next full to prevent too much cross contamination.

There are a few other little things that are not immediately obvious unless you have operated the machines or have a tank in the hand. Again, you will probably find this out as you actually start to test your prototype for development with film and chemicals (not just fluid dynamics) .

Bests,
C

[AndrewBurns]

Calebarchie, yeah sorry I've been very busy with my day job (https://www.rocketlabusa.com/) and trying to get a friend to assist with the control electronics side. Also trying to get some quote and hopefully some prototype sheet metal parts ordered soon so I can start building up the frame of the machine a bit. Yes I am concerned about surge marks to do with the way the fluid is entering, I originally had a bit of a baffle inside of the tank to divert fluid around but I'm going to try without as it would probably end up foaming the chemicals up. The fluid enters the tank through an oblong hole/slot which should be under the level of the film in the tank and so there shouldn't be any direct impingement onto the film but as you say I'll find out once I start testing and using silicone moulds initially mean that changes are not really expensive to make if I need to.

[AndrewBurns]

I know it's been a while since my last blog post but I haven't spent all of the time sitting on my hands, new post is up:

http://midtonemachines.com/news/sheet-metal-and-valves-oh-my/

Sheet metal parts are on the way and I've started life-cycle testing of the pinch valve design I intend to use, to make sure that it's going to be suitable for heavy commercial use (and therefore bulletproof for home use). I also included some of the photos I've been taking recently instead of working on the machine :P all on my Chamonix 4x5 with Ektar and developed at home.

[Duolab123]

I know it's been a while since my last blog post but I haven't spent all of the time sitting on my hands, new post is up:

http://midtonemachines.com/news/sheet-metal-and-valves-oh-my/

Sheet metal parts are on the way and I've started life-cycle testing of the pinch valve design I intend to use, to make sure that it's going to be suitable for heavy commercial use (and therefore bulletproof for home use). I also included some of the photos I've been taking recently instead of working on the machine :P all on my Chamonix 4x5 with Ektar and developed at home.

I see you are looking at thermoforming. I worked for Whirlpool and Maytag in refrigerator engineering, we would run in line and rotary vacuum thermoforming machines that would form in a "double bubble " the fresh food and refrigerator interior cavity liner in one stroke, these units were typically 22 to 25 cubic foot interior volume, about 70 inches tall 33 to 36 inches wide. I started in Amana Iowa in 1994, I still think that and co-extrusion were the most fun part of the operation. I can't remember the cycle time but it seems like we formed a set of liners every 90 to 120 seconds. The biggest co-ex line would extrude ABS sheet around 6 foot wide probably 20 feet / min.
Maytag built a plant in Reynosa Mexico, Whirlpool bought Maytag/Amana we sold the plant to Fisher Paykel. Small world.

[AndrewBurns]

I see you are looking at thermoforming. I worked for Whirlpool and Maytag in refrigerator engineering, we would run in line and rotary vacuum thermoforming machines that would form in a "double bubble " the fresh food and refrigerator interior cavity liner in one stroke, these units were typically 22 to 25 cubic foot interior volume, about 70 inches tall 33 to 36 inches wide. I started in Amana Iowa in 1994, I still think that and co-extrusion were the most fun part of the operation. I can't remember the cycle time but it seems like we formed a set of liners every 90 to 120 seconds. The biggest co-ex line would extrude ABS sheet around 6 foot wide probably 20 feet / min.
Maytag built a plant in Reynosa Mexico, Whirlpool bought Maytag/Amana we sold the plant to Fisher Paykel. Small world.

I can only imagine how large and heavy the molds were for that! The vacuum forming production tooling I'm looking at is machined aluminium and I believe they also include heating and cooling in the mold to assist cycle times (not that I believe that will be an issue for my small volumes).

I've also just done a test of the pump filling and draining the developing tank, I can fill the 4-reel tank in 12 seconds which I think is well fast enough to avoid uneven development. I will have to look at improving the drainage however as it isn't very efficient at getting the dregs of the chemicals back out again.

Also pinch valve is now up to 7000 cycles and still going strong.

[calebarchie]

Position and slope!

[Duolab123]

I can only imagine how large and heavy the molds were for that! The vacuum forming production tooling I'm looking at is machined aluminium and I believe they also include heating and cooling in the mold to assist cycle times (not that I believe that will be an issue for my small volumes).

I've also just done a test of the pump filling and draining the developing tank, I can fill the 4-reel tank in 12 seconds which I think is well fast enough to avoid uneven development. I will have to look at improving the drainage however as it isn't very efficient at getting the dregs of the chemicals back out again.

Also pinch valve is now up to 7000 cycles and still going strong.

Yes there's temperature control in the molds, it's been many years back since I was directly involved. The foam insulation between the inner and outer walls required massive tooling cores and outer support structure, you can lift a truck off the ground with polyurethane foam. As I recall most of our aluminum molds and foam cores were made in Italy. Amazing craftsmanship. Today, as with injection molding tooling, I suspect China is a major player.

12 seconds sounds great to me, it takes me that long to pour solutions into my Jobo with the lift.

We used "Thermolators" to maintain foam core temperature, would heat at beginning, then chilling (heat pumps) would come on to take the enormous amounts of heat out of the foam tooling from the exotherm. Every 3 1/2 minutes one fixture produced a foamed cabinet. With 40-50 fixtures you could make a lot of big refrigerators.
Looking forward to seeing further progress.
Best Regards Mike

[nbagno]

I can only imagine how large and heavy the molds were for that! The vacuum forming production tooling I'm looking at is machined aluminium and I believe they also include heating and cooling in the mold to assist cycle times (not that I believe that will be an issue for my small volumes).

I've also just done a test of the pump filling and draining the developing tank, I can fill the 4-reel tank in 12 seconds which I think is well fast enough to avoid uneven development. I will have to look at improving the drainage however as it isn't very efficient at getting the dregs of the chemicals back out again.

Also pinch valve is now up to 7000 cycles and still going strong.

12 seconds is the time I use on my Jobo from the start of lifting the handle on the lift to pouring in the next solution.


Sent from my iPhone using Tapatalk

[AndrewBurns]

I've added a bit of a 'trench' to the bottom of the develop tank to allow fluid to better fill/drain, I've taken some video of the process yesterday but now I need to learn how to edit videos to chop it all together (I'm an engineer, not a youtube vlogger...)

Also the pinch valve is well over 10000 cycles now and still going strong, there are some small fissures on the inside of the silicone tube now but it still holds pressure without leaking. The gear train of the servo looked fine at 10k cycles so if I had to bet I'd guess the first part to fail will be the silicone tube splitting at >20k cycles. These valves will cycle between about 1 and 5 times per tank of film developed so we're already talking a lot of film through the machine at this point (>8000 rolls of 35mm). The good thing about the tube failing first too is that it's extremely easy to replace, and my aim is to make the machine user-serviceable with spare parts and repair manuals available.

[AndrewBurns]

New blog post, now with a video of the develop tank filling and draining! The pinch valve is over 16000 cycles without problems and the sheet metal components have arrived. It's really starting to look like a machine, not long until film is being developed I think.

http://midtonemachines.com/news/water-flow-testing-and-more-valves/

Direct link to the video:

https://www.youtube.com/watch?time_continue=41&v=RXbx7h3p17Y

[Peter De Smidt]

Looking good!

[Tin Can]

Agree!

[Two23]

Something like this should have happened years ago.


Kent in SD

[Duolab123]

Very neat.

[AndrewBurns]

Just dropped the hammer on getting 10 production prototype develop tanks made, and a bunch of other parts required to continue building up the machine, watch this space! I'm really trying to get this thing developing film before the end of the year.

[Duolab123]

Very good. Looking forward to seeing results.

[calebarchie]

Just dropped the hammer on getting 10 production prototype develop tanks made, and a bunch of other parts required to continue building up the machine, watch this space! I'm really trying to get this thing developing film before the end of the year.

Nice, you didn't want to test the 3D printed one for development before then?

[AndrewBurns]

Nice, you didn't want to test the 3D printed one for development before then?

The 3D printed one wasn't really the correct material for fully functional testing, it wasn't black and opaque for keeping light out and the heat deflection temperature of the resin isn't really as high as I'd like (also not sure about the chemical resistance). I also needed one or two other parts made so I got them all done together, I'm still going to use all 3D printed parts for the valves for the time being.

[Duolab123]

The 3D printed one wasn't really the correct material for fully functional testing, it wasn't black and opaque for keeping light out and the heat deflection temperature of the resin isn't really as high as I'd like (also not sure about the chemical resistance). I also needed one or two other parts made so I got them all done together, I'm still going to use all 3D printed parts for the valves for the time being.

So are you still planning on vacuum casting with PU? Should be bulletproof.

[AndrewBurns]

So are you still planning on vacuum casting with PU? Should be bulletproof.

Yep I have 10 sets of parts on the way with vacuum cast PU, I hope they're bulletproof! Luckily with a set of 10 of everything coming I can sacrifice one or two tanks to destructive testing with some abnormally rough use.

[Duolab123]

Yep I have 10 sets of parts on the way with vacuum cast PU, I hope they're bulletproof! Luckily with a set of 10 of everything coming I can sacrifice one or two tanks to destructive testing with some abnormally rough use.

Depends on the exact formula. Bowling balls are made with PU resins, it's tough stuff.

[calebarchie]

The 3D printed one wasn't really the correct material for fully functional testing, it wasn't black and opaque for keeping light out and the heat deflection temperature of the resin isn't really as high as I'd like (also not sure about the chemical resistance). I also needed one or two other parts made so I got them all done together, I'm still going to use all 3D printed parts for the valves for the time being.

Still would of been possible to run it in the dark to develop B&W and test for even dev :) But probably easier to just go ahead and order sample, hopefully no changes will be required (still would of been nice to do phototherm cross-compatibility). How much did it set you back if you don't mind me asking?

[AndrewBurns]

$1500 USD for 10 machines worth of parts (not just the develop tank, but also a few other parts used elsewhere in the machine). Speaking of which, the parts arrived today and they look great!

https://www.facebook.com/midtonemachines/posts/507222046776680

http://i.imgur.com/QCZJjGZm.jpg (https://imgur.com/QCZJjGZ)

http://i.imgur.com/ap5Tqn1m.jpg (https://imgur.com/ap5Tqn1)

http://i.imgur.com/7JLSA3xm.jpg (https://imgur.com/7JLSA3x)

http://i.imgur.com/SPG9FrLm.jpg (https://imgur.com/SPG9FrL)

[Duolab123]

[QUOTE=AndrewBurns;1518339]$1500 USD for 10 machines worth of parts (not just the develop tank, but also a few other parts used elsewhere in the machine). Speaking of which, the parts arrived today and they look

Very exciting, how are you planning to test? I'm a recent retiree, I worked in home appliances, we did testing to failure, (if done correctly a refrigerator door weighted with lead, will go at least 300,000 cycles before falling off :o ) and some field testing, usually with employees. Field tests are great but expensive, we would need to retrieve everything that was pre production do to safety certifications (UL, CSA etc.)

[AndrewBurns]

$1500 USD for 10 machines worth of parts (not just the develop tank, but also a few other parts used elsewhere in the machine). Speaking of which, the parts arrived today and they look

Very exciting, how are you planning to test? I'm a recent retiree, I worked in home appliances, we did testing to failure, (if done correctly a refrigerator door weighted with lead, will go at least 300,000 cycles before falling off :o ) and some field testing, usually with employees. Field tests are great but expensive, we would need to retrieve everything that was pre production do to safety certifications (UL, CSA etc.)

One of the servo pinch valves has done 16000 cycles before I stopped the test (no failure). I'll be using the prototype machine for all of my personal photography once it gets going, which will be at least a few sheets of 4x5 per week. I also plan to get some of the early beta machines out to other local people and potentially one commercial lab for testing.

[AndrewBurns]

New blog post is up:

http://midtonemachines.com/news/let-the-programming-begin/

I've started wiring and programming the machine now, can make the valves open and close and the motors spin around. Actually making the machine function is trivial compared to making a nice user interface! But I don't want the user interface to be super cryptic or hard to use like something designed in the 80's so it's well worth the effort.

[AndrewBurns]

New blog post, sorry it's been a while:

http://midtonemachines.com/news/the-programming-continues/

Programming is more or less complete for now and the machine is nearly at the level of functionality that would allow me to develop some B&W film (which is my goal for the end of the year). Next stop is designing up a custom PCB to save on wiring effort, clean the thing up a bit and combine a number of functions currently being handled by off-the-shelf boards.

[Duolab123]

New blog post, sorry it's been a while:

http://midtonemachines.com/news/the-programming-continues/

Programming is more or less complete for now and the machine is nearly at the level of functionality that would allow me to develop some B&W film (which is my goal for the end of the year). Next stop is designing up a custom PCB to save on wiring effort, clean the thing up a bit and combine a number of functions currently being handled by off-the-shelf boards.

Looking good. I used a machine back in the 80's, it was for old school wet chemistry Kjeldahl nitrogen determination. It was 10 times more complicated. Imagine mixing concentrated sulfuric acid with 50% sodium hydroxide then steam distilling the whole mess.


Your plan of simplifying the wiring etc will clean up the bit of tangle. Looks great.
Best Regards Mike

[AndrewBurns]

New post up, nearly done designing the custom PCB's that will clear out the current wiring rats-nest and make manufacturing/production of the machine faster and cheaper.

http://midtonemachines.com/news/pcb-design/

[Duolab123]

Looks very nice. And yes your time is best spent doing what you are doing. Steady progress.
Best Regards Mike

[AndrewBurns]

PCBs are done and working, I've also put together a dummy body shell out of laser cut MDF for testing purposes, that I think also looks pretty good given that it's just for testing:

http://midtonemachines.com/news/finished-pcbs-and-dummy-body/

[nbagno]

PCBs are done and working, I've also put together a dummy body shell out of laser cut MDF for testing purposes, that I think also looks pretty good given that it's just for testing:

http://midtonemachines.com/news/finished-pcbs-and-dummy-body/

Gr8!


Sent from my iPhone using Tapatalk

[Louis Pacilla]

The shell, as does other parts sure looks a lot like my Phototherm SSK8

[AndrewBurns]

Yeah as I've said in previous blog posts I didn't intend for it to turn out that way when I started the project, I actually intended it to look a lot more like the filmomat, but as I started working through the various choices I had I worked out that for my target market the various features of the Phototherm unit make a lot more sense. That said the internals are significantly different between the two, different pumps, valves, heater system, control unit etc. So think of it as a smaller and (hopefully) cheaper SSK8 with totally modernised internals that will be just as if not more capable and much easier to use.

[Duolab123]

Looks great. Galvanic corrosion, previous life I was involved with the use of stainless steel for home appliances. Terrible application for stainless. We had pitting corrosion issues no matter what alloy. Contamination from carbon steel, homeowners using steel wool, you name it. If everything is the same alloy no problem.

I showed a manager why we had to use all stainless fasteners. I stuck a piece of the 300 series SS in a potato and a galvanized steel screw in the other end and showed him the voltage on a multi meter. We had no more streaks of red (or white ) after that. :o

[AndrewBurns]

More progress, new custom PCBs are in and they've done a great job clearing up all the wiring mess, a much better solution for production. A few niggles with the pinch valves are holding me back a bit but I've still had the machine pumping water in and out of the developing tank with the agitation motor going. Again pretty close to being able to develop B&W film right now but I'd rather iron out all of the bugs before that.

http://midtonemachines.com/news/pcbs-integrated-and-more-cad/

[AndrewBurns]

Just a short video update for today, showing the LCD screen and user interface that you'll use to operate the machine. Also the developing tank filling and draining with water while the agitation motor operates.

http://midtonemachines.com/news/short-video-update/

[Peter De Smidt]

Looking very good!

[Duolab123]

Very nice. Looks like you are almost ready to try a couple units in the real world. Will you be using a formed cover? Since it's low voltage do you need any agency approvals to sell?
I'm amazed at the progress in such a short time.

[AndrewBurns]

Thanks for the support!. The cover will eventually be thick vacuum formed plastic but I need to get an idea of production volumes before I get them made, the wooden cover allows me to progress with the design and testing of the machine until then. I specifically looked for an external power supply with CE and FCC approvals so that the machine itself won't require specific certification as it doesn't contain any dangerous voltages or fall under any other hazard categories. That said, I believe that if I wanted to sell it through retail stores in the USA it would probably require UL certification (but it's unlikely these will ever be sold retail).

[pound]

impressive work done so far.
any indication of price level?

[Daniel.E]

I've been following along since the beginning and it's so impressive! A couple of questions, would you use standard reels or at some point use Jobo reels? the Jobo being smaller allow for smaller tanks and less chemistry, that'd be neat. What are the planned tank capacities? And I second the price point. I'd be one of the first ones to order one!

[Fred L]

agree with Daniel re: Jobo reels. If you made the drum and core to accept Jobo steel reels (for 15xx tanks), that could possibly entice Jobo users looking for a smaller, automated unit...like me perhaps ;)

[Duolab123]

Paterson reels are 1/3 the price of Jobo. The AP reels shown, are very popular, inexpensive. I use Jobo reels because of my processor, but they are finicky until you learn the nuances of loading, especially with 120. MHOFWIW.

[Fred L]

Paterson reels are 1/3 the price of Jobo. The AP reels shown, are very popular, inexpensive. I use Jobo reels because of my processor, but they are finicky until you learn the nuances of loading, especially with 120. MHOFWIW.


Sorry for the fuzziness, I only use Hewes steel reels. the two teeth for the sprocket catch are a godsend for loading film ;)

[Duolab123]

Sorry for the fuzziness, I only use Hewes steel reels. the two teeth for the sprocket catch are a godsend for loading film ;)

I've got Hewes for Jobo/Paterson columns, and yes there's no better reel. This type should work fine on this setup. A caution, the weight of the SS reels may be an issue. I've found the plastic Jobo reels put a lot less strain on the motor of my smaller Jobo, not sure how this would effect this machine.
Best Regards Mike

[AndrewBurns]

Haven't actually used any of the JOBO reels, I'll have to get my hands on some for testing. If they're smaller then maybe it would only require a different spindle to take them in the same tank (which wouldn't save chemistry but would allow you to use the reels). Ultimately it will come down to how much demand there is, as Duolab as said the AP patterson style reels are pretty good and quite cheap, and also probably easily available second-hand, so compared to the cost of the machine I don't think reels will be that big of an outlay.

[ic-racer]

I tested Patterson reels in the mid 1980s with rotary processing and found the plastic spiral comes too close to the image area of 120 film and I got over-development at the very edges. Films and chemistry have changed since then, so maybe the effect will not be seen. I'd check that this will not be an issue if the plan is to use Patterson reels.

[AndrewBurns]

Another new blog post, new company logo and some website updates: http://midtonemachines.com/news/new-logo-shout-outs-and-progress/

The machine is now fully capable of processing B&W, I'm actually starting to run out of things to do on it now, so I'm going to have to start doing the boring things like making a BOM (bill of materials) to figure out how much it actually costs to make one...

[calebarchie]

RE: Name, why not something that pays tribute or homage to what it was originally based off aka Phototherm.

Bests,
C

[Duolab123]

Well maybe Burns-O-Matic, :o

Midtone Rapid Color Processor

[AndrewBurns]

Midtone RFP-4? (rapid film processor 4, for 4 rolls of 35mm per tank)

[calebarchie]

Midtone RFP-4? (rapid film processor 4, for 4 rolls of 35mm per tank)

The first version of the Phototherm was the FP-1, although rapid kind of implies something like a x-ray film dev process.

[Daniel.E]

I'd say something simple like Midtone Machine AFP-4

[AndrewBurns]

New blog post up and new name for the machine, it's now officially the Chromabox-4

I'm struggling with my ancient 3D printer while in isolation so I'm looking for suggestions for when I'm able to shop online again, let me know if you have an idea of what printer I should get!

http://midtonemachines.com/news/pinch-valves-heaters-and-names/

[Duolab123]

Leaking valves. 30 years ago when I was still working as a chemist we did a lot of manual titrations. Teflon stopcock Pyrex burette. 1/10 molar HCl never seeped around the stopcock. 1/10 molar NaOH just wouldn't stay in the burette, after about 30 minutes you would see some leakage, if you left it over the weekend, we would come back to a crust of dry sodium hydroxide around the joint.
I have tanks with floating lids dilute working solution of hypo clearing agent, doesn't leak through the self closing tap, if I try to store the 5X concentrate it seeps and clogs the valve. This stuff is mostly sodium sulfite solution.

[AndrewBurns]

Managed to print enough valve parts to retrofit the prototype and the leaking is gone. I've also got the heater systems up and running nicely. Here's a really short teaser video of the Chromabox-4 in action, cycling through 6 different 'chemicals' one after the other. What you don't see is the automatic water and air flush cycles that happen between different chemicals to prevent cross-contamination (which would have been visible in the video as colour contamination between the different bottles).


https://youtu.be/-Y_88YVmjBs

[calebarchie]

Chromabox-4...? Hmmm not feeling it, let me know when you produce retrofit tanks for Phototherm machines

[AndrewBurns]

Chromabox-4...? Hmmm not feeling it, let me know when you produce retrofit tanks for Phototherm machines

Enjoy your phototherm while it lasts!

[ic-racer]

I have been following form afar, but can you give a brief synopsis of the current setup as it looks like refinements have been done since I first saw this.

The tank does not spin, the reels spin in the tank (YES?)
What type of reels will fit?
How is temp. regulated, is there a water bath?
Is there a cleaning cycle or what to do between sessions?
Are you using a roller pump, or do the chemicals go into the pump mechanism?

Even though I have a Jobo CPP2, it would be nice to have something that can be setup and taken down quickly for one or two rolls of film.

Thanks

[AndrewBurns]

I have been following form afar, but can you give a brief synopsis of the current setup as it looks like refinements have been done since I first saw this.

The tank does not spin, the reels spin in the tank (YES?) Yes
What type of reels will fit? Anything that fits into a Patterson style tank, although I've yet to test a wide range of spools
How is temp. regulated, is there a water bath? No water bath, chemicals are pre-heated in a separate tank before being pumped into the developing tank. The developing tank sits on a heated pad to maintain temperature during the process
Is there a cleaning cycle or what to do between sessions? It does an automatic clean between each chemical during the cycle, it's recommended that the last step in a cycle is water and after that it should be nice and clean for the next run. There will also be a specific cleaning program to run if you want to change the chemical channels around
Are you using a roller pump, or do the chemicals go into the pump mechanism? It's a gear pump, the pump wetted components are all compatible with common photographic chemicals (stainless steel and PPS plastic)

Even though I have a Jobo CPP2, it would be nice to have something that can be setup and taken down quickly for one or two rolls of film.

Thanks

ic-racer I've replied to your comments above in bold. The Chromabox-4 is much smaller than the JOBO CPP2 and because it doesn't use a water bath to heat chemicals it doesn't take a long time to get up to temperature, so it should be perfect for doing a few rolls here and there. I'd imagine the CPP would be better if you wanted to do a lot of film at once or some prints or really large negatives. Because the Chromabox-4 is fully automatic too you just need to push the button and walk away, during testing I'm often running the machine through a cycle while I'm doing something else around the house.

[AndrewBurns]

Coming up on the 1 year anniversary of starting the project, I've had a lot of life getting in the way recently and that always takes precedence but now I'm trying to get back on track and have made a new blog post of my recent progress.

http://midtonemachines.com/news/level-sensors-at-last/

I finally got the floating level switches I ordered and 3D printed a prototype of the new heating tank, everything going well so far. I need to get back into modifying the firmware but programming really isn't my favourite task so it's hard to get started (once I'm doing it I don't mind so much though).

[ic-racer]

Thank you for taking time to answer the questions. Congratulations on the anniversary.

[Duolab123]

Coming up on the 1 year anniversary of starting the project, I've had a lot of life getting in the way recently and that always takes precedence but now I'm trying to get back on track and have made a new blog post of my recent progress.

http://midtonemachines.com/news/level-sensors-at-last/

I finally got the floating level switches I ordered and 3D printed a prototype of the new heating tank, everything going well so far. I need to get back into modifying the firmware but programming really isn't my favourite task so it's hard to get started (once I'm doing it I don't mind so much though).

Looks very nice. What is the size/ capacity of the heating tank? In my previous life we would make aluminum tooling for injection molding prototyping, helped alot. Aluminum tooling might be adequate for low volume production??.

Anyhow looks great.
Best Regards Mike

[AndrewBurns]

Mike, the heating tank is just over 600mL of chemicals, enough for 4 rolls of film. From what I've seen the break-even point of injection molding when compared to other techniques such as resin casting is about 300 parts, I'm not sure how many of these machines I could sell but for the time being I'm assuming there won't be enough demand to make injection molding cost effective (would be great if I were wrong though!).

[Duolab123]

600mL that makes sense. I wonder what kind of educational market there is for something like this????
E6 market seems to no longer require mounting slides. For a camera shop that still processes C-41 with a minilab, but sends out E6 and black and white this might be a good idea.
It really looks neat, good luck.
Best Regards Mike

[AndrewBurns]

New blog post is up, I've had a 'version 2' of the sheet metal parts manufactured and moved all of the prototype machine components onto that, looks a lot cleaner now and is super sturdy! I have to make some design changes to the heating tank again so that it drains better, but that's the beauty of being able to 3D print functional parts during prototyping.

http://midtonemachines.com/news/sheetmetal-version-2/

[AndrewBurns]

http://midtonemachines.com/news/bits-and-pieces/

New blog post up, new heating tank that's working well, some ease-of-use firmware updates, getting some parts injection moulded etc. I've also added the ability to send the used chemical from any channel to any other channel, which allows for even easier replenishment without any external hardware.

[Duolab123]

http://midtonemachines.com/news/bits-and-pieces/

New blog post up, new heating tank that's working well, some ease-of-use firmware updates, getting some parts injection moulded etc. I've also added the ability to send the used chemical from any channel to any other channel, which allows for even easier replenishment without any external hardware.

Do you have provision for tempered water wash cycles? If you use Kodak Flexicolor process C-41RA like all C-41 processing Developer 3'15", Bleach (Process C-41 RA) is 1 minute, or longer if you prefer, followed by fixer, 2 minutes. Minilab machines run 3 consecutive stabilizer baths instead of a water wash. The method most folks at home use is several water wash cycles followed by Kodak Flexicolor Final rinse. The final rinse is a wetting agent with a biocide to preserve the gelatin of the finished negative. One single stabilizer bath without a wash step to get rid of the fixer is not adequate. Kodak specs the wash 2 min at 38°C , the non RA C-41 uses washing for 3 min 24-38°C

[AndrewBurns]

Duolab, yep there's a separate line into the machine (separate from the 6 x chemical lines) for wash water. The pre-programmed cycles will include washing between each chemical and also at the end and the wash water is heated up to the process temperature. If you were to make your own recipe then you can do as much or as little washing as you'd like and heat the wash water to whatever temperature you like (between 20 and 45 degrees celcius that is), although I would encourage a wash between each different chemical unless you want some carry-over/cross-contamination because there's always a few drops left in the tanks and on the film even after draining.

[Duolab123]

Duolab, yep there's a separate line into the machine (separate from the 6 x chemical lines) for wash water. The pre-programmed cycles will include washing between each chemical and also at the end and the wash water is heated up to the process temperature. If you were to make your own recipe then you can do as much or as little washing as you'd like and heat the wash water to whatever temperature you like (between 20 and 45 degrees celcius that is), although I would encourage a wash between each different chemical unless you want some carry-over/cross-contamination because there's always a few drops left in the tanks and on the film even after draining.

Brilliant! I'm looking forward to further reports!

[AndrewBurns]

Another blog post update, I now have a 4x5 sheet film holder in the machine and it looks like maaaybe it could take a 5x7 holder?


http://midtonemachines.com/news/a-lick-of-paint/ (http://midtonemachines.com/news/a-lick-of-paint/)

[ic-racer]

Looking good!

[AndrewBurns]

Big news update this time, the Chromabox has finally processed some film! It's been a while coming... Just two sheets of FP4+ 4x5 today but they turned out great (IMO). I've also confirmed that the Chromabox-4 can also take up to 4 x 5x7 sheets at a time. More details in my most recent blog post:

http://midtonemachines.com/news/mission-accomplished-kinda/

https://live.staticflickr.com/65535/50499191978_a91210ac0c_b.jpg (https://flic.kr/p/2jWrypL)

https://live.staticflickr.com/65535/50500062937_26163df023_b.jpg (https://flic.kr/p/2jWw2ji)

[AndrewBurns]

Just thought I'd bump this thread with some more news. The Chromabox-4 is now routinely processing film during testing and I'll be hosting a demo-day at a local film lab soon to get more rolls of film through it. I'll also be running some C41 test strips through it on the day to check how close the process is to the Kodak standards and tweak as needed.

I shot and developed two sheets of 4x5 Ektar in the machine a few days ago, results were pretty good I think!

https://live.staticflickr.com/65535/50815585791_40b985f58f_b.jpg (https://flic.kr/p/2kqpagv)

https://live.staticflickr.com/65535/50815584816_6089e38d74_b.jpg (https://flic.kr/p/2kqp9YG)

I also participated in a 'fireside chat' webinar hosted by the magazine Silvergrain Classics yesterday which I assume will be uploaded to youtube in a few days. I'm not sure I did that good of a job explaining Midtone Machines and the Chromabox but there seems to be a lot of interest and it was nice to meet some other people from the industry.

[Andrew O'Neill]

Cool! Is the Photrio crowd aware of your work?

[AndrewBurns]

Cool! Is the Photrio crowd aware of your work?

Potentially? I think I've posted there once or twice before but I've never made a specific thread over there. I suppose that's something I should be doing.

[Andrew O'Neill]

Potentially? I think I've posted there once or twice before but I've never made a specific thread over there. I suppose that's something I should be doing.

I think you should. Mainly film shooters over there, including myself.