Zone VI Compensating Developing Timer

[Mike Troxell]

I was looking at the Calumet site today and I noticed they are selling the Zone VI Compensating developing timers again. I thought they had quit makeing these. Maybe they saw all the interest in used ones and decided to go back into production with the timers.

[paulr]

I always liked the compensating metronome. Not sure if that's still made. It makes printing so easy ... step on the pedal for light, take your foot off when you need to stop and grab another tool (or a drink) and just count clicks. Helps keep burning and dodging consistent from print to print also. only drawback is you have to turn the music down. and after 4 in the morning or so it can be challenge for me to count too high above 15.

[Jeff Corbett]

Paul - this post is regarding the compensating development timer, not the enlarging timer. Mike - I got my timer on the used market (and they do command high prices). Sure glad to hear they may be making them again. Have you confirmed that they really are making them, and it's not just a hold-over on their website? When I tried to get one from Calumet, their website still listed the timer even though it was not available new from Calumet.

[paulr]

Sorry, my misunderstanding.
Question about the timer: does it allow you adjust the curve of the temperature/time relationship, or does it make the (wrong) assumption that all developers respond similarly to temperature change?
I have a lower tech, foolproof solution that can be adapted for any developer. If anyone's interested I can post intstructions on how to do it. Maxim Muir published it in his black and white newsletter a few years ago.

[Sal Santamaura]

"Question about the timer: does it allow you adjust the curve of the temperature/time relationship, or does it make the (wrong) assumption that all developers respond similarly to temperature change?"

I don't know if there are any internal trimmers that someone familiar with the circuitry could adjust to accomplish that, but it has no such external controls. Given Fred Picker's material choices, it's probably set up for Tri-X in HC-110.

[neil poulsen]

From the outside, there is no way to adjust the curves. Perhaps there are some "pots" or something if you opened up the timer. Not sure.

However, I took some data and did a comparison with the curves on the Ilford site for HP5. For each one degree F difference from that temperature specified by the Ilford curves, my timer's compensation would be off by approximately 3 seconds. (With the timer turned to the film setting, versus the paper setting.) I had no way to evaluate the paper setting of the timer.

Assuming that the Ilford curves are accurate, that's not too bad. I use my timer for all film and paper development. Versus relying on the timer for large differences in temperatures, I try to stay close to the specified temperature using a water bath and let the timer compensate for any small variation in temperatures thereafter.

[Peter Langham]

I have owned one for years. The timer is set up for Tri X and HC 110. There is no way to adjust it. Have found it lent alot of consistency to my paper developing too.

Peter

[Jorge Gasteazoro]

There is a way to adjust it, but you have to open it. If you do open it there are two screw adjustment wheels, one on the far right and one on the far left about 1/3 down from the top of the circuit board. The right hand adjustment, adjusts the slope of the curve or, IOW the percentage change for each degree of change in temperaure. Leave this one as is, it is about right regardless of developer. The left one takes care of the "set" temperature, this is the one you want to adjust if you want your "normal" temperature to be higher or lower than the 68 ºF that is set to. I adjusted mine to read 74 ºF as the base temperature .
There is nothing to it, BTW make sure you unscrew only the screws in the corners, if you do the middle ones, you will loosen the circuit board.

[Jacques Augustowski]

The curve depends on the developer agent used. Metol has a diferent curve than hidroqinone.
I have used it with D-76 and it gave me no problems. What will be neat is to try to put the termistor
(sensing probe, I think it was 5K ohms) inside a Jobo tank with a sort of rotating external contacts to send the info to the meter.
Jacques

[Jorge Gasteazoro]

I know the curve depends on the developer, but the setting they use is pretty much average and it is a good reference, unless you are willing to open the gizmo every damn time you change developers.

I beleive you meant metol has a different curve than phenidone as most developers are a combination of these two with Hydroquinone. You would be surprised how close the curves are once they are mixed.

Do you have a Zone VI timer?

[Mike Troxell]

Jorge,

How accurate do you think it would be with pyro?

[Jorge Gasteazoro]

I have used it with ABC and now with Pyrocat and I get very consistent results. For best results you have to standarize and make your development tests with this timer at diferent temperatures to see if it is giving you best results, specially if you fiddle with the temp setting. The timer is very consistent, Jobo makes one too, but I bet it is outrageously expensive.

Bottom line the % adjustment seemed to work very good with ABC and Pyrocat. YMMV.

[Jacques Augustowski]

Do you have a Zone VI timer?

--Jorge, 2004-10-29 22:44:41

Hi Jorge,
I have one bought from Zone VI, I think 9 years ago and still working fine..
Jacques

[paulr]

For film development, I always just get the soup to the right temperature.

For paper, I compensate, but I do it based on tests that I've done in the past. The developers that I use are radically different in how they respond to temperature. The main difference is that Metol and phenidone respond in a pretty linear way to temperature over a wide range; hydroqhinone does not. It has a much steeper curve, and then plummets at lower temps. It's basically innert at 50 degrees (and this can be in issue when you live an print in a loft in 100+ year old brooklyn factory). The difference between a meol-only developer and a metol-hydroquinone developer are not subtle.

Testing is actually easy, because there's a direct relationship between the emergence time of an image and total developing time. You can work with a consistently exposed gray swatch, and note its emergence time at 68 degrees in one developer. From that point you can do the same thing in one or two degree increments above and below, however far you think you'll need. From this information you can extrapolate the total deveoping time for each temperature. If the emergence time is 10% longer at 65%, then you know the total developing time is 10% longer too. Repeat for whatever other developers you use.

I made a little chart for each developer I use. The leftmost column has the actual developer temp; the next columns are headed with various "normal" developing times that I use at 68 degrees ... like 1 minute, 1.5 minute, 2 minutes, etc..
In the boxes of the chart are the adjusted devoloping times. After one annoying afternoon of testing, I was done. Using the system couldn't be easier. I typically use two tray development (a low and a high contrast developer), so this means two charts above my trays. I recheck the temp a couple of times over the course of a long printing session to make sure things haven't changed.

Here's why this degree of accuracy can be important: I found that untoned prints would often look identical despite slight differences in developer temperature, but the differences would become pronounced after toning. Especially with nelson gold toner, which I use most of the time. With the correct amount of development, I get a nice cool brown. If there's too much development (from the soup being too warm) the toner gives a red brown. If there's too little development (from cold soup) I get inconsistent toning, including ocasional split toning. Tightening up the temperature/time controls completely eliminated the inconsistencies and a whole lot of grief. I don't believe it would be possible to get the same level of accuracy from a compensating timer that treats all developers equally.

[Ron Mc]

<<I was looking at the Calumet site today and I noticed they are selling the Zone VI Compensating developing timers again....>>

Now if they would bring back the 120 rollfilm loader...

Ron