View Full Version : Zone VI Compensating Enlarging Timer with Beseler MX45 ?

17-Dec-2014, 06:14
I've just acquired a Zone VI Compensating Enlarging Timer and the Photodiode that comes with it. I have a Beseler MX45 Enlarger. Any suggestions on how to utilize the Photodiode? Or would I be forced to install a Zone VI Cold head that has this built in?


17-Dec-2014, 10:22
What head does the MX 45 have? If it's a cold light head, you should be able to install the photocell. L

17-Dec-2014, 13:01
It's the standard bulb/incandescent head

Peter Lewin
17-Dec-2014, 14:01
You should be able to install the diode in any head, but I'm puzzled about what you are trying to accomplish. I have the compensating enlarger timer connected to my ZoneVI VC head, and it's primary purpose is to hold times constant even if I vary contrast, since it measures the total light output of the yellow and blue tubes. Stated differently, I make a test strip at a given contrast setting, choose a time, and make a print. If I decide to change the contrast setting, I don't have to make another test strip, because the timer compensates for the new contrast setting. If you are using a non-variable-contrast head, especially an incandescent head where the output is not as temperature dependent as an unstabilized cold light, I don't know what benefit the compensating timer gives you.

17-Dec-2014, 15:14
I'm trying to be able to use the zone vi timer. To use it, I must utilize the photodiode. But I have a incandescent bulb, not a cold head. Unless I connect the photodiode, the unit does not work.

neil poulsen
17-Dec-2014, 16:31
I've done exactly this with my Zone VI compensating timer. I have a spare Omega D2V head in which I've installed an extra sensor I bought years ago from Calumet. Here are the two things I would worry about:

>> Keep the sensor away from heat. I really don't know if excessive heat would be a problem, but I decided to avoid finding out.

>> You may want to consider using reflected light off shiny metal, versus putting the sensor in the direct path of light. The point being, you probably won't want to overwhelm your sensor with light that's too bright. (It depends on how quickly the "seconds" click by when using the timer.)

I also have a Zone VI sensor installed on my Beseler 45s color head that has a bright, quartz halogen lamp. The 45s has a piece of shiny metal (not a mirror) that reflects light from the lamp to illuminate the dials on the front of the head. It works perfectly to place the sensor in the path of that reflected light. (keep in mind, that there's quite a bit more installation detail to using a compensating timer with this head. If you're interested, I can provide a summary.)

While the intensity of light will influence how quickly "time" clicks by on the timer, these timers also have an adjustment screw that can be used to determine the speed of clicks. (Does the audible portion of your timer work properly?)

18-Dec-2014, 11:22
I installed a sensor in my Durst CLS 301 dichroic head so I could use my Metrolux timer with it. Unfortunately, I cannot find a location where the sensor will see both bulbs, so it's mounted over one of the bulbs. Being ELH bulbs, the light output should not vary, esp since my EST 301 power supply is stabilized. I snaked the sensor in through the vent in the back, so did not need to drill a new hole and taped it to the top housing near one of the bulbs. Since the head is fan cooled, I have not had any issues with heat. L