F-Stop Timers

Some background. I use a Beseler MXT with a Zone VI (Aristo) Cold Light Head. I plan to upgrade soon to the V54 lamp. I have a Zone VI Stabilizer and A Zone VI drydown timer that has knobs that allow me to set it anywhere within a range of .1 seconds to 10.9 seconds.

I've begun to practice rudimentary f-stop and split-grade printing. I would like to use a setup that is more amenable to f-stop and split-grade than I currently have.

I understand that the v54 lamp will shorten my exposure times as the old lamp with a Y40 filter works for VC printing but with very long exposures.

First question:

Am I correct in assuming that in addition to swithcing lamps, moving over to an f-stop timer means swapping it for the Zone VI timer but that I will still employ the Zone VI stabilizer?

I'm looking at both the offerings from RH Designs and from Darkroom Automation.

Second question:

Are there other manufacturors that I should be aware of?

RH Designs' Stopclock Vario is designed for cold light heads and has "a compensating feature which measures the light output from the enlarger lamp and adjusts the exposure to compensate for any changes."

Third question:

Does this mean that it replaces the stabilizer as well as the timer?

RH Designs' ZoneMaster II meter can be used with the Vario as a separate tool but not connected to it, as it can with their StopClock Professional. Their Analyser Pro encorporates both the timer and the meter.

Fourth Question:

Is the Analyser Pro compatible with my cold light head?

The Darkroom Automation F-Stop Timer (with or without their separate meter) is a much simpler device and is much less expensive.

Fifth Question:

Can someone with some persoective on working with these devices tell me how significant a sacrifice one makes if opting for the much smaller feature-set of the Darkroom Automation products?

Thanks in advance for any answers to these questions. I'm hopeful that this thread will be useful to other people that have similar questions about selecting an f-stop timer.

I have the Stopclock Pro. I use it with a Durst 138s w/condensers. It is a very fine product. Dr. Richard Ross is the one (albeit biased) to ask these questions. Are you going to upgrade the cold light head to the Aristo 4500? If not, how do you intend to split filter print without filters? Also, if you use the Vario, it is my understanding that the probe will act as a stabilizer for the light source. My Stopclock has a dry down compensation built in to it so that unit can go. It has two channels so split filter printing is very easy. I did not want to have "program" my timer so that is why I did not choose the Analyzer Pro. I just make test strips with the soft light filter on channel 1 and then when I need to I switch to channel 2 for the hard light filter. I split filter every print I make.

I don't think Darkroom Automation timers offer anything but the f/stop timing. If it were me, I would buy the RH Designs timer again.

lee\c

lee said:

I have the Stopclock Pro. I use it with a Durst 138s w/condensers. It is a very fine product. Dr. Richard Ross is the one (albeit biased) to ask these questions. Are you going to upgrade the cold light head to the Aristo 4500? If not, how do you intend to split filter print without filters? Also, if you use the Vario, it is my understanding that the probe will act as a stabilizer for the light source. My Stopclock has a dry down compensation built in to it so that unit can go. It has two channels so split filter printing is very easy. I did not want to have "program" my timer so that is why I did not choose the Analyzer Pro. I just make test strips with the soft light filter on channel 1 and then when I need to I switch to channel 2 for the hard light filter. I split filter every print I make.

I don't think Darkroom Automation timers offer anything but the f/stop timing. If it were me, I would buy the RH Designs timer again.

lee\c

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Sorry if I wasn't clear. I will use filters for split-grade. The Y40 filter I use now is to color-correct the existing Aristo lamp for VC papers. If I get the appropriate lamp, I won't need to color-correct it. In either case I'd be using 0 and 5 filters for split-grade.

So it looks like if I go with either the Vario (with or without the ZoneMaster II meter) or the Analyser Pro, I will be able to get rid of both my timer and my stabilizer, yes?

I will read the Analyser Pro manual and learn about the programming to which you refer and see how daunting it would be.

The Analyser Pro is a lot less expensive than a Vario plus a ZoneMaster II. I'm not clear on whether or not the Pro will take the ZoneVI probe the way the Vario does.

jstraw,

I figured you would need the filters. I think you might be better off if you find a place that sells Rosco filters and find a green and a blue that replicate the Green 58 Wratten filter and the Blue 47b Wratten filter. Use the green filter for soft tonality and the blue for the hard or shadow tonalities. These filters are the color of the two tubes that Aristo and Zone VI use in there VC heads.
I maybe totally wrong but I under the impression that the Vario is the only timer that supports the Zone VI style probe. I am also unclear why anyone but maybe the beginning rookie might need an Analyzer Pro instead of the full feature timer like the Stopclock Pro. Maybe just my bias. Also, order the foot switch.

I know you are in KS from your info under your name. I am in FT Worth and I would be glad to give a demo of the Stopclock at my darkroom if you want to drive down before you pony up the money. Just PM me and let me know and we can work out a time.

lee\c

I will toss in my recommendation for the RH Designs products. (I haven't seen or used the other brand, but know that they have been around for a long while and began by marketing a well regarded entry level DIY kit!) As does Lee, I have the Stop Clock Pro. It is superbly engineered to allow me to focus on getting the image that I visualize. As your preliminary ventures into f-stop timing probably revealed it is a very intuitive exposure system. You base your exposure very much like one would do with film.

I will also concur with Lee's guidance to contact Richard at RH Designs. You are looking at a unit that offers different control functions than what I am using. But it would appear to me that you would continue to use the voltage stabilizer.

I will share that I am having difficulty getting my SCP to interface with the 1000w color head on my Durst 184. This is not a fault of the SCP, it is not designed to power 1000 watts. Richard is helping me sort out the wiring of an intermediate relay to buffer the SCP from the heavy load. I can tell you first hand that I am very unhappy using a regular timer and approximating the time display on the SCP. I do not believe that you will be fully able to benefit from the f-stop timing system trying to use charts, calculations, etc. I did not fully appreciate the wonderfully designed user interface of the SCP until I couldn't use it!

Cheers,
Geary

galyons said:

I will share that I am having difficulty getting my SCP to interface with the 1000w color head on my Durst 184. This is not a fault of the SCP, it is not designed to power 1000 watts. Richard is helping me sort out the wiring of an intermediate relay to buffer the SCP from the heavy load......

Click to expand...

Is your 1000w color head the Durst CLS1840? I ask because I have used the 1000w Durst CLS1840 color head which is powered by the EST1000N power supply. It was my understanding the EST1000N power supply had a built-in relay to protect the timer, and in practice, I used a small mechanical timer with no problems. I’m interested because now I use the SCP, and was considering hooking up the SCP to the CLS1840. I would certainly be interested in your solutions.

lee said:

jstraw,

I figured you would need the filters. I think you might be better off if you find a place that sells Rosco filters and find a green and a blue that replicate the Green 58 Wratten filter and the Blue 47b Wratten filter. Use the green filter for soft tonality and the blue for the hard or shadow tonalities. These filters are the color of the two tubes that Aristo and Zone VI use in there VC heads.
I maybe totally wrong but I under the impression that the Vario is the only timer that supports the Zone VI style probe. I am also unclear why anyone but maybe the beginning rookie might need an Analyzer Pro instead of the full feature timer like the Stopclock Pro. Maybe just my bias. Also, order the foot switch.

I know you are in KS from your info under your name. I am in FT Worth and I would be glad to give a demo of the Stopclock at my darkroom if you want to drive down before you pony up the money. Just PM me and let me know and we can work out a time.

lee\c

Click to expand...

I appreciate the advice regarding filtration. So, you favor those rosco filters over grade 0 and 5 PC or MG filters? At what stage do you apply filtration, below the lens?

Also, I must be confused. I thought the Analyser Pro was everything the StopClock Pro is and more, not less....that it is more fully-featured. Am I getting that wrong?

Thanks for the offer to demonstrate the timer. I'll definately consider it!

Eric, the head is a Pavelle 403. The power supply is EPOI for US distribution. There is no relay in the transformer unit. I really want to get this sorted and will keep you posted.

Cheers,
Geary

resummerfield said:

Is your 1000w color head the Durst CLS1840? I ask because I have used the 1000w Durst CLS1840 color head which is powered by the EST1000N power supply. It was my understanding the EST1000N power supply had a built-in relay to protect the timer, and in practice, I used a small mechanical timer with no problems. I’m interested because now I use the SCP, and was considering hooking up the SCP to the CLS1840. I would certainly be interested in your solutions.

Click to expand...

jstraw said:

Also, I must be confused. I thought the Analyser Pro was everything the StopClock Pro is and more, not less....that it is more fully-featured. Am I getting that wrong?

Thanks for the offer to demonstrate the timer. I'll definately consider it!

Click to expand...

No, your original premise is correct. The Analyzer Pro is an upgade, basically combining the Stop Clock with the ZoneMaster meter/analyzer.

Cheers,
Geary

galyons said:

Eric, the head is a Pavelle 403. The power supply is EPOI for US distribution. There is no relay in the transformer unit. I really want to get this sorted and will keep you posted.

Cheers,
Geary

Click to expand...

I don't want to hijack the thread, but my issue with the SCP switching the Pavelle 10x10 head is resolved. Bad relay, shorting out of the box. Replaced the relay. The SCP and I are happy!!

Cheers,
Geary

I use the StopClock Vario with a Beseler Dichro 45S head. I don't really use the "vario" cold light probe but I bought thinking that some day I might want to try a cold light.

The timer is one gadget I would not want to lose. It has completely changed the way I print and even the way I think about printing. Also, I make better prints because of it. Well worth the money. Definitely get the footswitch. If I did it again, I might buy 2 footswitches because they seem flimsy comapred to the timer which seems very well built.

I also recommend their flashing devise. Without it, I don't think I would have bothered to experiment with flashing but now I find it very useful at times.

I'm not very familiar with the Zone VI heads other than the VC version and the Compensating Timer. If you have a Stabiliser, I assume this is intended to fix the old cold light problem of varying intensity. A voltage stabiliser alone won't do this for cold light, but a purpose-built cold-light-stabliser will. If you have one of those then you don't need a compensating timer. In which case you can quite happily use an Analyser Pro without problems - or indeed a standard StopClock Professional and/or a ZoneMaster II.

To clarify - the Analyser Pro is not the same as a StopClock Pro + ZoneMaster combination; its timer is not so sophisticated. There is only one channel, no dry-down compensation (which you won't need anyway if the meter is properly calibrated to your equipment) and no programmable exposure sequences (although there is a neat burn-in feature).

A compensating timer such as the Zone VI one or our StopClock Vario measures the light output from the enlarger lamp and adjusts the exposure time to compensate for any changes. If the lamp gets brighter, the time gets shorter so that the print exposure remains constant, and vice versa. The issue here is with exposure metering; any exposure meter bases its calculations on the light level it sees when you make a measurement. If that light level subsequently changes (due to lamp output fluctuations) then the calculation will be wrong. A compensating timer can correct for this. However, if the light level changes during measurement (our meters typically require two or more measurements to establish exposure and contrast) then the compensating timer cannot correct the exposure.

In summary, we have many users of Analysers and ZoneMasters together with cold light enlargers who get good results. Providing the tubes are well warmed up prior to printing and left on as much as possible the light output variations are minimised.

For best results with cold light I recommend either a compensating timer such as our StopClock Vario, or a lamp stabiliser. You do not need both. The latter route allows more accurate exposure metering, but if you prefer to establish exposure and contrast by making test strips then either will work just as well.

Hope that helps!

Cold light heads present a bit of a problem when used with any timer be it an F-stop unit or a linear timer. As the tube warms up the amount and spectrum of the light changes and it also changes as the tube ages. Some cold light sources are very sensitive to dips in line voltage. Additionally there is a delay each time the lamp turns on and this delay time has some variation to it. As Richard mentioned, the most viable solution is to use a stabilized power supply or closed-loop intensity control and to keep the lamp warm.

A compensating timer, correctly called a ‘light integrator’, will help a lot but is not a panacea. Proper integrators for use with cold lights and HID lamps do exist and my firm has been developing them, along with stabilizing power supplies, since 1979. These systems have only been used for pre-press graphic arts, an industry that succumbed to computerization quite a while ago and is now quite moribund.

The contrast control on the older Zone VI heads - the one with the letters ‘A’ - ‘H’ on a pair of knobs - has a few holes in it’s range of contrast adjustment and most workers use these heads in split grade mode. The newer ZVI LED head does not have this problem. If you need to split-grade print with the older head then the RH timer may be more to your liking.

The Darkroom Automation timer and meter are designed for use with contrast filters, VC/color dichoric heads and LED heads. Although lacking the RH timer’s split-grade and compensating features the Darkroom Automation timer has easier to use dodging and burning controls and a more flexible test strip facility. The RH timer displays seconds that are adjusted up and down by variable stop increments. The DA timer is a pure stop-timer and displays and adjusts time in stops.

Only you can make the decision as to which equipment will meet your needs. That can be hard unless you can play with the equipment. F-Stop timers are a small market that can’ t support a large distributor and dealer network. Even if you can find a local photo-shop they won’t have any DA/RH/Nocon/Unique timers you can try out.

Darkroom Automation’s timers and meters come with a 30-day satisfaction guarantee. You can try one out and if it doesn’t meet your needs you are only out the return postage. I don’t know RH’s policy on this, but I see Lee has offered to show you his RH unit.

Most important, have fun.

Whew - a lot of info in this thread, most of it about the timer issue.
My twocents on the head and filters:
I use an old Zone VI timer with foot switch (old fashioned, I guess, but works for me) with an Aristo head. See here - http://www.aristogrid.com/prod02CC_CL45.htm . This head has a filter drawer for standard 6" Ilford filters (placing them in the light path, where they won't degrade the image sharpness). The bulb is the new V54 designed for use with VC papers. When I built the darkroom, I put the enlarger on its own circuit (even the bulb heater and timer are on a separate circuit). I have never had variation that I can see (I'm pretty discerning about this, and Allen Johnson, the old president of Aristo told me it would work).
The reason I did not buy the dual bulb head (http://www.aristogrid.com/prod02BA.htm) is that it doesn't have the brightness of the CL45 (confirmed by Aristo) - it's also a lot cheaper. I find that with Forte V VC fiber, exposures are longer than they ever were with graded papers (Ilford, Seagull, and others over the years). I have no direct comparisons, but I think about 2 stops longer, for a small print, probably longer for a large print due to RF.
A grade 1.5 to 1 (with the Forte paper, LPD 1:2) is probably close to a grade 2 Seagull G-2 graded paper, for me.
One other thing, I bought an extra filter drawer to faciliate swapping filters, especially with burning and dodging.
I also had to rig up some felt gasketting and a large 4" wide elastic band (some stuff from the fabric shop made for elastic beltlines on pants) wrapped around the head to plug up all the leaks. But I love the results with this paper and Selenium toner.
If you want to know more about my experience with this setup, PM me.

Flipping through old magazines, I came across a blurb in the August 1992 issue of Camera and Darkroom for the Stouffer S/L 1 timer that functioned in both seconds and logarithmic modes. Nowhere in the blurb does the term "f-stop" appear. It listed for $625.

Ooh, an article on F-Stop Timing in the March, 1991 issue...