OK to use Zone VI sensor with V54 bulb?

[Larry Kellogg]

Hello,
So, I picked up this head from eBay, an Aristo 5x7 cold light. The head has the older W45 bulb in it, and it looks like someone retrofitted it with the Zone VI sensor. If I upgrade to the V54 bulb, 57-LO-V54, which is available from Louis Kessler and the good people at VoltArc, is it ok to use the new bulb with the Zone VI sensor? I have a RH Designs Stopclock Vario which I will use with this head.

I have included some pictures.

Larry

[KennyMark]

Yes, it is ok.
Unless the amount of light produced by the lamp is outside of the limits of the sensor to detect and create a current based on the light measured, it should work with any lamp. All it does is create a current proportional to the amount of light measured at the sensor. The timer recalculates the time needed based on that current that it measures throughout the exposure.

[Drew Wiley]

I've done it that way for years, with the ZVI sensor above a big V54 unit. But I have it connected to a simple beeper, not any kind of feedback box. Just be careful
to properly warm up your cold light first, and place the sensor at some point relatively diffused or neutral relative to the cold light, since the perimeter bends of the tubes sometimes behave a little differently than the more usable main area of the grid.

[Kevin Crisp]

Works fine for me too with the compensating enlarging timer.

[Larry Kellogg]

Thanks everybody.

Could people tell me the advantages of the V54 bulb over the old W45 one that I have? I have read a lot of threads but am still not sure.

[Ginette]

Actually the sensor is installed in a bad place.
As you have a RH Designs Stopclock Vario, look at the manual, they explain very well how to install the probe http://www.rhdesigns.co.uk/darkroom/StopClock_Pro_Vario_UM_v85.pdf p25-26

[KennyMark]

Thanks everybody.

Could people tell me the advantages of the V54 bulb over the old W45 one that I have? I have read a lot of threads but am still not sure.

Larry,
There are multiple threads here that discuss this topic. IIRC, the most important difference is the color of the light for printers using VC or MG papers. The newer lamp is better suited for both split printing and achieving the full range of contrast grades. Please read those threads though rather than trusting me. The newer lamp should also be brighter unless I misunderstand. Someone more knowledgeable on this topic please chime in.

[Larry Kellogg]

Thanks a lot for pointing out that the sensor is in a bad place! It is in the corner where the tube comes out. The StopClock manual says that the sensor should be in the middle of the tube grid, with the sensor pointing towards the diffuser. I hope I have enough wire to get the sensor in the middle of the grid.

By the way, it doesn't seem that obvious to me which side is the sensor side, I don't see a shiny blue sensor, I guess it is on the opposite side of all the blobs of solder. Anybody know?


Actually the sensor is installed in a bad place.
As you have a RH Designs Stopclock Vario, look at the manual, they explain very well how to install the probe http://www.rhdesigns.co.uk/darkroom/StopClock_Pro_Vario_UM_v85.pdf p25-26

[Kevin Crisp]

The V54 bulb works with modern multigrade filters and modern papers. If you just print fixed grades there is no real advantage to it. Many sources say you can use various yellowish filters to get the older bulb to work but I tried those suggestions and none of them work really and I was very glad I upgraded the bulb.

I also put the Zone VI sensor looking right in the middle of an outside tube, not in a bend.

[Kevin Crisp]

Yes, looking at your photo, I'd say the sensor side is the one that doesn't have the solder points on it. My Zone VI sensors don't look much like that. But if it works, it works.

[Larry Kellogg]

Yes, looking at your photo, I'd say the sensor side is the one that doesn't have the solder points on it. My Zone VI sensors don't look much like that. But if it works, it works.

I guess I had better plug it in and try to make some prints to see if it works. ;-) How do I test to see if it works? Is it possible to get another sensor if this one does not work? I think the RHDesigns people could help me out.

[Kevin Crisp]

I didn't note from your initial report that you weren't using a zone VI device. Since I am not familiar with a stopclock vario I can't help you. The idea of the feedback loop is to give you even exposures even though the output of the bulbs can increase significantly as they warm up. So if you expose a print for 10 seconds with a cold head, then do the same think in about 20 minutes after it warms up, I'd say it is working.

[Larry Kellogg]

The StopClock Vario has an indicator that lights up when it detects the presence of the light sensor, as long as you hit the focus button: "Sensor (StopClock Vario) When the light sensor is connected and has been detected (by switching on the enlarger using the Focus key) this indicator lights."

I messed up some prints in them middle of a printing session once when I turned off the timer to reset its state, and started printing again without first hitting the focus button. I'll try out the lamp and see how it does. It does seem like the V54 bulb is worth getting, for convenience.

Larry


I didn't note from your initial report that you weren't using a zone VI device. Since I am not familiar with a stopclock vario I can't help you. The idea of the feedback loop is to give you even exposures even though the output of the bulbs can increase significantly as they warm up. So if you expose a print for 10 seconds with a cold head, then do the same think in about 20 minutes after it warms up, I'd say it is working.

[Larry Kellogg]

Hmm, another question, how am I going to adapt this head for use on the Zone VI 5x7 Type II enlarger I own? Did they make some kind of adaptor plate?

Larry