Midtone Machines Chromabox Automatic Processor

mshchem said:

Looks good! I've been processing a bit of E-6 lately. Using a newer Jobo. It works great, however it's huge to accommodate upto a 20x24 inch print. The idea of a automated smaller unit is definitely attractive.
Best Regards Mike

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test_realm said:

Andrew do you have a price point in mind for the chroma box? Apologies if it's been discussed and I've missed it.

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• How does it control for temperature loss when pouring chemicals into a cold tank? How about natural cooling that happens during development without a tempering bath? In my experience a 500ml tank loses almost a 1C in 4 minutes.
• Are chemicals heated in real time during pumping?
• How much time does it take to fill up the tank? Is tank rotating during pouring?
• Will JOBO reels fit? Asking because they allow for two 120 rolls per reel.

McDiesel said:

@AndrewBurns Love this! For your upcoming FAQ, here's a few I have:

• How does it control for temperature loss when pouring chemicals into a cold tank? How about natural cooling that happens during development without a tempering bath? In my experience a 500ml tank loses almost a 1C in 4 minutes.
• Are chemicals heated in real time during pumping?
• How much time does it take to fill up the tank? Is tank rotating during pouring?
• Will JOBO reels fit? Asking because they allow for two 120 rolls per reel.

Also, my understanding that the pump used is similar to what's in espresso machines? What is the expected lifetime in terms of cycles? I've had those fail on me in the past.

Thank you.

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• The machine measures temperature in the developing tank and over-heats (or under-heats) the next chemical to compensate for temperature lost during pumping and for temperature lost (or gained!) if the tank and film are at a different temperature to the target. The developing tank sits on a silicone heat pad which is controlled to maintain a constant temperature in the developing tank during the cycle regardless of how long it is (it doesn't need to do much, just make up the heat lost to the environment).
• The chemicals are heated in an internal tank prior to pumping, the next chemical in the process is being heated while the current chemical is in contact with the film. That way when the current chemical time is up the next chemical is ready to go at temperature.
• Filling the tank takes about 20 seconds, the film is rotating while the tank is filling (or draining). I haven't noticed any uneven development with 135, 120 or 4x5 in B&W or C41. Rotation is selectable between three different speeds and you can also select either single-direction or two-direction rotation.
• The current shaft size only fits Patterson type reels, but I have plans to also offer a smaller diameter shaft that will take JOBO 1500-series reels in the future. Also I believe there are some aftermarket Patterson-compatible reels available that have the 'film gate' like the JOBO ones so that you can load 2 x 120 rolls onto a single reel.
• The machine doesn't use a vibration-type pump like the Phototherm or domestic coffee machines, it uses a gear pump (with stainless steel body and PEEK gears) which should be good for a minimum of a few thousand hours continuous operation. Given that pumping is only a small fraction of the total cycle time this should work out to many years of solid use even at a lab. One lab using my prototype machine has done a bit over 300 hours operation in 6 months solid use, but of that the pump might have only been running for maybe 100 hours so it's not breaking a sweat.

Steven Lee said:

What happened to this processor? The website is dead but I have not seen any announcements anywhere online.

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