Cold Light Source Inquiry

I am using an Aristo D2 Cold light source with a single lamp, not the 2-Color (yellow & blue) that come with the VC version. I am also using a generic GraLab "Clock-Like" timer at the moment and would like to upgrade to get better, more consistent results. I have heard good things about the Zone VI Compensating Timer working with Cold Light Sources and have a chance to get a used one - but the owner does not have a stabilizer cable (don't know if this needs one or not). My question, if I am not using the VC Cold Light Source and only using the Single Lamp Cold Light Source will I benefit from upgrading my older GraLab Timer to a Zone VI Compensating Timer? Do I HAVE to have that extra stabilizer cord with photocell? How much of an advantage will I see staying with a single-lamp cold light and using Zone VI compensating Timer?

Please help, Thank you,

Cody Thomas

Yes, you have to have the photocell cable - without it there is no compensation feature. I assume it has some feature that lets it work without the cable - though it is possible the timer will sit there like a lump on a rock and do nothing. Calumet may supply replacement cables, but check the price - it may be more than you are paying for the second hand timer.

Without the cable you are better off sticking with your present timer.

If you are not having noticeable problems with print to print consistency you will not notice any improvement using the compensating timer. If you are having problems (such as a 2nd print is always noticeably darker) then the timer (with cable) may improve things.

I'm using an Omega D-II with an Aristo Hi-D head, V54 tube, and a Metrolux compensating timer.

If your cold light head has a separate heater circuit and you allow it to warm up before using it, then you won't notice a huge difference with a compensating timer, but you will see a slight improvement in consistency, and you'll be able to get consistent results even if the head isn't warmed up and with shorter exposure times. Consistency will go from "pretty close" to spot on.

If your cold light head doesn't have a separate heater circuit, you'll notice a very significant increase in consistency with a compensating timer, unless perhaps you leave the light on all the time and use a shutter or a black card to control exposure time.

For a compensating timer to work, you do need to install the photocell probe.

If your enlarger output and timer are spot on, it's easier to use very short exposure times for production printing, or very short, precise burn/dodge times. If I want to do a run of, say, 40 postcards, four-up on 8x10" paper, with an exposure time of 3.6 sec., for instance, I can expose them one after the next and develop them all in a batch and be confident that the first one will look just like the last one.

Go thru the Aristo contactor or you risk damage to a digital timer. Damage may not occure right away, but may over time. Mechanical timers ( Timeo Light) are ok either way.

Ronald Moravec said:

Go thru the Aristo contactor or you risk damage to a digital timer.

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Only if it is a very badly designed / very old digital timer - current timers should have no problems.

David A. Goldfarb said:

If your cold light head doesn't have a separate heater circuit, you'll notice a very significant increase in consistency with a compensating timer, unless perhaps you leave the light on all the time and use a shutter or a black card to control exposure time.

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This is correct.
I do not have a compensating timer and use exposures of 30 -50 secs to minimise timing errors. The lamp is allowed to warm up for 5minutes before use and left on for the session. If you use this method then ensure that the enlarger is vibration free as far as possible. I get no inconsistency problems.
Regards,
John.