New Compensating Process Timer

RH Designs · Apr 9, 2008

Here's a progress update on the new Process Timer. The big news is that it will be fully compensating for temperature changes using a sensor probe which can be placed in the tank or tray, in a water bath, or stuck to the outside of a developing tank with such as Blu-Tack. The prototype is working well and we're just tweaking the firmware to improve the ergonomics over the original ProcessMaster which by any measure wasn't the easiest device in the world to set up .

Briefly, the spec is as follows:

Stores up to 8 processes, each of up to 9 steps in length
Each step can be 5sec - 2 hours long
Optional temperature compensation over a range of approx 15-40 degrees C at a choice of rates, allowing for almost every combination of film and developer
Optional factorial development facility for prints, increasing dev time as the dev exhausts - choice of factor from 2 - 6
Optional display of percentage or actual time remaining
Timer pause and resume
Pause at the end of each step or auto advance to the next step
Dimmable display
Optional audible beep for agitation and during the last 10 seconds of each step
Extra status indicators
Footswitch

The good news for existing ProcessMaster owners is there will be an upgrade available!

Comments and suggestions on the above spec are welcome - I can't promise any changes will be acted upon but we will consider all of them. In particular, the sensor is currently housed in a stainless steel tube 3mm x 50mm with 1m of cable attached. It fits through the "twizzle stick" of a Paterson dev tank allowing agitation by twisting the stick, or if as I do you prefer inversion agitation, you can fit a suitable cable gland to the tank lid which allows the probe to be placed in the fluid but prevents leakage when the tank is inverted. This should work for other tanks too. See attached pics. It's not too late to change the size of the sensor housing or cable length so if you have any observations please let me know asap!

I expect the ProcessMaster II to be available in approximately two months, at an introductory price of £149 inc VAT (£126.81 outside the EU area). I will add it to our web site shortly. You can then place advance orders - we won't take any money off you until it's ready to despatch!

Fintan · Apr 9, 2008

Excellent, I will take one please Richard

Fintan · Apr 9, 2008

Loud beeps please. Thin Lizzy sometimes accompany film development.

arigram · Apr 9, 2008

Sounds very nice.
Funny that I have been making designs of my own for a Process Meter, but never though of including a thermometer with automatic compensation!

I assume that it would work fine with a Jobo rotary processor, by just dipping the meter inside the basin. Yes, the Jobo would keep the temperature constant but the Meter having memory and steps would make it really useful just as well. Plus, sometimes you are running the Jobo at a higher than normal temperature for one reason or another.

David A. Goldfarb · Apr 9, 2008

Sounds like a great timer. I'd be interested.

I'm trying to think of processing sequences that I do in the dark that it might not be able to handle, but I can't think of any offhand.

The most complicated, I suppose, might be tray or tank/hanger development where I've got multiple development times. I want to insert the first sheets in at the beginning of development, the next group after a few minutes, and then a third group a few minutes later, and I want an agitation beep every 15 sec, auto advance to the rinse for say 30 sec., and then to the fix for 3 min with an agitation beep every 1 min. If I understand the specs correctly, I could do that.

I suppose the wash sequence could be its own program, if I wanted to do something like a standing wash sequence with an exchange of water at 1 min, 3 min, 7 min, 12 min, 20 min, and 30 min.

And it would be good to be able to run two or more processes at once, so I could wash and start processing the next batch at the same time. I don't know if you've got that option. Different beeps for different processes.

When I use daylight tanks, I use stainless, so I guess I could attach the probe to the outside of the tank with a couple of rubber bands. The cord would have to be long and flexible enough to allow for inversion, and durable enough that it wouldn't crack easily with fatigue over time, and that there would be a simple repair option that the user could accomplish with ordinarily available materials in case RH Designs isn't around when it becomes an issue. If the tank drips, it's also important that chemicals can't drip down the cord and short out the plug.

RH Designs · Apr 9, 2008

Thanks for the useful feedback David -

David A. Goldfarb said:
I want to insert the first sheets in at the beginning of development, the next group after a few minutes, and then a third group a few minutes later, and I want an agitation beep every 15 sec, auto advance to the rinse for say 30 sec., and then to the fix for 3 min with an agitation beep every 1 min. If I understand the specs correctly, I could do that.

You should be able to all of that except the 15 sec beeps - they are every 30 sec.

I suppose the wash sequence could be its own program, if I wanted to do something like a standing wash sequence with an exchange of water at 1 min, 3 min, 7 min, 12 min, 20 min, and 30 min.

That could be one process, yes.

And it would be good to be able to run two or more processes at once, so I could wash and start processing the next batch at the same time. I don't know if you've got that option. Different beeps for different processes.

That's getting a bit complicated . You would need two timers for that really, it would be very hard to see how to do that with a single one given only one time display, and the opportunities for getting mixed up could be a problem.

When I use daylight tanks, I use stainless, so I guess I could attach the probe to the outside of the tank with a couple of rubber bands. The cord would have to be long and flexible enough to allow for inversion, and durable enough that it wouldn't crack easily with fatigue over time, and that there would be a simple repair option that the user could accomplish with ordinarily available materials in case RH Designs isn't around when it becomes an issue. If the tank drips, it's also important that chemicals can't drip down the cord and short out the plug.

Good points. I stuck the probe to the outside of my Paterson tank last night with Blu-Tack, failing to realise that the Blu-Tack would be warm after kneading it and so the first couple of minutes went by a bit fast! Something to put in the manual ... Once everything equalised, it was fine. If sticking the probe to the outside of the tank, stainless tanks would be better as heat conduction isn't that brilliant through plastic. The cable on our sample probe is PTFE and about 2mm diam - I think we'll probably use PVC on the production ones. Either way, it's plenty flexible enough. We'll seal the plug end of the cable as well as the sensor end. RH Designs should be around at least as long as I'm still around .

RH Designs · Apr 9, 2008

arigram said:
I assume that it would work fine with a Jobo rotary processor, by just dipping the meter inside the basin. Yes, the Jobo would keep the temperature constant but the Meter having memory and steps would make it really useful just as well. Plus, sometimes you are running the Jobo at a higher than normal temperature for one reason or another.

It should still be just as useful with a Jobo, yes. Immersing the probe in the tank as I did with my Paterson tank should also be possible - the cable won't get badly twisted because the Jobo reverses. The only issue I suppose is whether there's enough chemistry in the horizontal tank to wet the probe properly, although the surrounding air ought to be at the same temperature!

David A. Goldfarb · Apr 9, 2008

RH Designs said:
You should be able to all of that except the 15 sec beeps - they are every 30 sec.

Would it be hard to offer the option of 15 sec. beeps? Pyro developers often do better with agitation every 15 sec., particularly PMK, which is quite dilute.

RH Designs · Apr 9, 2008

David A. Goldfarb said:
Would it be hard to offer the option of 15 sec. beeps? Pyro developers often do better with agitation every 15 sec., particularly PMK, which is quite dilute.

It shouldn't be hard - I'll see what the software man says.

Rick Jones · Apr 10, 2008

I'm concerned that where the top of the probe and connecting wire meet could be subject to eventual leakage, possibly rendering the devise useless. What have you done to assure a permanent water tight connection at that point?

Brian Jeffery · Apr 10, 2008

Richard,

I'm currently processing film with inversions at 1 minute intervals, however I'm going to be looking at 3 and 5 minutes intervals for some film/developer combinations. So I would really be interested in the 30 second beeps being variable: either from a predefined list (15 sec, 30 sec, 1 min, 3 min, 5 min) or infinitely variable within specific parameters. I personally think this would make this timer indispensable as it is something that I cannot do with a normal kitchen timer and it would mean that I'm less likely to inadvertently perform an inversion at the wrong time.

Can you confirm that the end of process sound is different to the 30 second beep?

Brian

RH Designs · Apr 10, 2008

Rick Jones said:
I'm concerned that where the top of the probe and connecting wire meet could be subject to eventual leakage, possibly rendering the devise useless. What have you done to assure a permanent water tight connection at that point?

We are working with our supplier to ensure as far as possible that this doesn't become a problem. Currently the joint is sealed by adhesive-lined heat-shrink tubing.

rmann · Apr 10, 2008

How about a junction/socket on the cable allowing for cables of different length, different types to be plugged in? I could see having a cable/probe for tray use, and a different cable attached to a tank lid. Short cable for trays like a meter in length would be fine, for tanks maybe something a little longer would work better.

RH Designs · Apr 10, 2008

Brian Jeffery said:
Richard,

I'm currently processing film with inversions at 1 minute intervals, however I'm going to be looking at 3 and 5 minutes intervals for some film/developer combinations. So I would really be interested in the 30 second beeps being variable: either from a predefined list (15 sec, 30 sec, 1 min, 3 min, 5 min) or infinitely variable within specific parameters. I personally think this would make this timer indispensable as it is something that I cannot do with a normal kitchen timer and it would mean that I'm less likely to inadvertently perform an inversion at the wrong time.

Can you confirm that the end of process sound is different to the 30 second beep?

Brian

Currently the device beeps twice on the minute, once on the half minute. Variable beeps I'm afraid are not really practical - there is a time display so you can keep track of the minutes, or if you're tray developing in total darkness with the display covered you could use the cricket umpire method of transferring marbles from one pocket to another in order to keep track of the minutes . The end of step beep is longer than the agitation prompts, and is preceded by a ten second countdown.

RH Designs · Apr 10, 2008

rmann said:
How about a junction/socket on the cable allowing for cables of different length, different types to be plugged in? I could see having a cable/probe for tray use, and a different cable attached to a tank lid. Short cable for trays like a meter in length would be fine, for tanks maybe something a little longer would work better.

The connector is a standard 3.5mm stereo jack plug so you could use an easily obtainable extension lead or leads.

jeroldharter · Apr 10, 2008

rmann said:
How about a junction/socket on the cable allowing for cables of different length, different types to be plugged in? I could see having a cable/probe for tray use, and a different cable attached to a tank lid. Short cable for trays like a meter in length would be fine, for tanks maybe something a little longer would work better.

I second that. If not possible, then a 2 meter cord would be preferable so that the timer could be mounted to the wall.

It would be nice if the back of the timer had a couple of neodynium magnets (assuming they would not adversely affect operations) so that the unit could be easily mounted on a magnetic surface without drilling holes.

I like it that the timer is small, and probably light like the paper flasher. However, that means it will move easily when moving the cord around, fall into things, etc. So I would like some built in ways of securing it short of screwing it into the wall. I guess I could tape it or use blue tack but something more elegant would be nice.

For the footswitch, a long cord option would be nice. If I mount it on the wall and have to snake the footswitch behind the sink, etc. I would need a 3-4 meter cord. Also, I think that the footswitch for the timer is too light. It does not stay put and just the tension from the cord forces it out of position. Some type of weight in the bottom would make it more stable. A cool option would be to put a very dim, optional LED safelight in the footswitch so that it is easy to see in the dark.

Does it have a battery gauge? It would be frustrating to be processing film and the batteries die.

Peter De Smidt · Apr 10, 2008

I love my RH Designs timer. It's great!

At one time, I had a Zone VI compensating developing timer. It was the worst piece of darkroom equipment I've ever had. It had to be fixed 4 times, and of course it took awhile for me to figure out that it was broken! So I'm happy that RH Designs is going to build a better one, right?

One thing to remember is that at certain temperatures some developing agents simply stop working. Will this have some kind of warning? Will it say what the actual temp is?

Regarding use in a Jobo, the temp of the water bath is always a bit higher than the temp in the tanks.

Does all film respond to temp changes in the same way? I would expect that a 10% change in temp for TMX would make a bigger difference that a 10% change with Tri-x.

Anyway, just some things to consider.

RH Designs · Apr 11, 2008

jeroldharter said:
I second that. If not possible, then a 2 meter cord would be preferable so that the timer could be mounted to the wall.

It would be nice if the back of the timer had a couple of neodynium magnets (assuming they would not adversely affect operations) so that the unit could be easily mounted on a magnetic surface without drilling holes.

I can't see that being a standard fitment, but if you want to stick magnets to yours they shouldn't affect operation.

I like it that the timer is small, and probably light like the paper flasher. However, that means it will move easily when moving the cord around, fall into things, etc. So I would like some built in ways of securing it short of screwing it into the wall. I guess I could tape it or use blue tack but something more elegant would be nice.

It's based on the ZoneMaster II. It would be fairly straightforward to put keyholes in the base so it could be hung on screwheads.

For the footswitch, a long cord option would be nice. If I mount it on the wall and have to snake the footswitch behind the sink, etc. I would need a 3-4 meter cord. Also, I think that the footswitch for the timer is too light. It does not stay put and just the tension from the cord forces it out of position. Some type of weight in the bottom would make it more stable. A cool option would be to put a very dim, optional LED safelight in the footswitch so that it is easy to see in the dark.

Glow-in-the-dark tabs are available and much easier than adding an LED and the necessary extra battery. Heavier footswitches are available but they tend to be for industrial purposes and are very expensive. If it tends to slide about, try some self-adhesive Velcro pads or a big blob of Blu-Tack to stick it down. Extension cords are available. Believe me, for everyone who wants a longer cord, there'll be another who thinks it's already too long and gets in the way .

Does it have a battery gauge? It would be frustrating to be processing film and the batteries die.

Yes it does, or you can run it off the mains via an adaptor.

RH Designs · Apr 11, 2008

Peter De Smidt said:
One thing to remember is that at certain temperatures some developing agents simply stop working. Will this have some kind of warning? Will it say what the actual temp is?

Regarding use in a Jobo, the temp of the water bath is always a bit higher than the temp in the tanks.

Does all film respond to temp changes in the same way? I would expect that a 10% change in temp for TMX would make a bigger difference that a 10% change with Tri-x.

There will be over- and under-temp warnings, yes. If you know a definite minimum below which the dev stops working, please let me know and we'll make that the lower limit - currently it's 15C. There are two compensation rates which cover all the combinations we've investigated thus far.

jeroldharter · Apr 11, 2008

RH Designs said:
I can't see that being a standard fitment, but if you want to stick magnets to yours they shouldn't affect operation.

It's based on the ZoneMaster II. It would be fairly straightforward to put keyholes in the base so it could be hung on screwheads.

Glow-in-the-dark tabs are available and much easier than adding an LED and the necessary extra battery. Heavier footswitches are available but they tend to be for industrial purposes and are very expensive. If it tends to slide about, try some self-adhesive Velcro pads or a big blob of Blu-Tack to stick it down. Extension cords are available. Believe me, for everyone who wants a longer cord, there'll be another who thinks it's already too long and gets in the way .

Yes it does, or you can run it off the mains via an adaptor.

Thank you for your replies. I could not live without my StopClock Pro. you obviously put alot of thought into your gear, so thanks. By the way, how much is this timer likely to cost?

Peter De Smidt · Apr 11, 2008

15c should be ok.

Fintan · Apr 12, 2008

One useful function of my current timer, is when I set it for say 5 mins for a lith print, if just approching 4 mins I think the print is going to pop I can ignore the timer beeps and it just keeps timing past the 5 minutes so for the next print I know to set it for 5 mins 25 sec for example.

RH Designs · Apr 12, 2008

Fintan said:
One useful function of my current timer, is when I set it for say 5 mins for a lith print, if just approching 4 mins I think the print is going to pop I can ignore the timer beeps and it just keeps timing past the 5 minutes so for the next print I know to set it for 5 mins 25 sec for example.

You can set it to run on past the zero point - it then counts up until you stop it. Then you can add that to the programmed time for the next print.

RH Designs · Apr 12, 2008

jeroldharter said:
Thank you for your replies. I could not live without my StopClock Pro. you obviously put alot of thought into your gear, so thanks. By the way, how much is this timer likely to cost?

Introductory price £149 inc VAT (£126.81 outside the EU area), likely to rise towards the end of the year.

Fintan · Apr 12, 2008

RH Designs said:
You can set it to run on past the zero point - it then counts up until you stop it. Then you can add that to the programmed time for the next print.

Excellent

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