Zone VI cold light

[d.s.]

I just got a Zone VI cold light with photo cell, stabilizer and timer. Well, I don't have it yet, But I was the high bidder and it's on the way. My questions:

I read somewhere that I'll need a filter because these lights are too blue? What filter? Where does it go? Are they still available?

Does anyone have a copy of the instructions that they can email me. It looks simple but I would like to know about the setting for lamp intensity and drydown/ exposure reduction. Any info about this unit would be greatly appreceiated.

I always check things out before I buy but this time I didn't have but a few minutes. The price didn't seem bad. I felt froggy and so I jumped.

Thanks, Croaking quietly

[j.e.simmons]

The regular cold light was made for use with graded papers. If you use graded papers, you would not need a filter. (That's how I use mine). I don't know the answer if you plan to use multigrade paper.

[Jorge Gasteazoro]

CAll Calumet and they will be glad to fax a copy of the instructions. If you bought the variable contrast head, dont worry, I had heard the same and bought a yellow filter, after tests I could not tell a difference between the prints with the filter and those without.

Good luck and enjoy the enlarger, they are wonderful machines.

[Reinhold Schable]

Here's a discussion regarding the V-54 replacement lamp for the Zone VI lamphouse that you may find interesting...

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=003PU4

(You may have to cut & paste this url, I haven't figured out how to link it...)

[Hans Berkhout]

With the original Zone VI diffuser you wil have a hot spot. Myrick Photographic in Monterey used to sell these thicker diffusers for about USD 10.00. You will also need an adapter (collar) to hold the light in place, in your enlarger. Howard Bond has written in Foto Techniques about the use of correction/printing filters that can be used with cold light heads for V.C. printing, it depends on the light tube (spectrum.

[Witold Grabiec]

I don't know how old your light head is, but when I purchased one new in 1992 there was no need for any correction filters and VC papers printed through it as expected (and most certainly no hot spots, how one gets a hot spot with a cold light is beyond me, unless intended).

Given the fact that it comes with a photo cell (assuming a factory installed one) you're likely to have no issue to worry about.

[Hans Berkhout]

The photo cell is part of the feedback system that adjusts exposure time if light intensity fluctuations occur. The central hot spot is caused by the fact that the grid (light tube) and it's housing are slightly undersized for a 4x5 negative. It is visible if you expose for say a zone 5-6 value without a neg in the carrier: there will be some fal-off.

[Doremus Scudder]

Hans is right about the light fall-off. Edge and corner burning are almost always necessary with this unit. That said, it is still the one I use most often. Regular VC filters will work with the V54 tube, but give slightly different results. Graded papers work better anyway (IMO). BTW Hans, can you let us know more about the thicker diffuser you have? Is it simply a thicker piece of white plexiglass, or is it something different. I'd like to pick one up.

Regards

[Witold Grabiec]

Ok then, light fall-off maybe, but not in my experience. That's not a hot spot though, a term used to describe uneven ilumination caused by bulb misalignment in old style heads where bulbs filament had to be properly focused against the mirror above it.

Would be interesting to confirm what that THICKER diffuser is all about. If it's simply a thicker piece of plastic, then it cannot compensate for light fall off caused by an undersized grid.

[Kevin M Bourque]

I had one of the original ones and it was just plain awful with VC paper, even with a yellow filter. These bulbs emit a non-continuous spectrum, so that they don’t respond to filters like an incandescent source.

Supposedly the new heads are better with VC. I don’t know how you know the difference by looking at it. Maybe Calumet can tell you.

[Mark Sampson]

I've used this head since '92 as well. Edge-burning is sometimes necessary, not from any "hot-spot" in the head, but from the undersized Omega D-2 it was designed to fit. In the 1940's they didn't expect you to print the full frame... so the round collar any cold-light head fits into is just slightly too small- the factory condensers are just the same. (When Zone VI designed their own enlarger,they made sure the light source was larger than the negative.)All that to one side, it's perfectly easy to print on variable-contrast paper with a Zone VI cold-light. Unfiltered you'll get higher contrast, with filters you'll probably use a lower-contrast filter than you might expect. My 'normal' filter is a Kodak #1, not a #2. You can put a CP40Y gel above the negative if you want. People suggest this to bring your 'normal' filter back to a #2. I tried this and found it unnecessary, plus it increases exposure times. Other people report uneven contrast grade spacing with the higher-number filters using this method. This has never concerned me, as I strive to make negatives that print on normal contrast grades, and seldom need to use a #4 or higher filter.

[RichardRitter]

All types of light sources have fall off. Some more noticeable them others. The best thing to do is burn the edges in. Some people have gone to the length of adding a gray disk to the back of the cold light housing. This disk is anywhere from 2 to 4 inches in diameter. You would have to run test to see what size works best for you. I use an oval disk behind my light. The thicker disk will only slow the enlarging times down.

If your are using the light for graded paper you don't need any filters.

Filters for VC paper. The light will give you a grade 4/5 hard print. Most people will tell you to add 40 CC of yellow them use a VC filter kit. This will slow your printing times way down. What I found works the best and keeps the printing time fast is to use the yellow filters from a color correction kit. 40 cc yellow will give around a grade 2 ½, 15 cc yellow around a grade 3, 80 cc yellow around a grade 1 ½. These are only ball park numbers. When I print with VC paper I never know what the final grade is. My objective is to make a print that I like. I most times when printing with VC paper will be split printing and/or printing one part of the image area will one filter and the other with something different.

The photocell is for the plugging in of the stabilizer or the comp. Timer made by Zone VI. These read the light and keep it consistence.

Dry down is the amount the paper gets darker as it dries. Papers run from 3% to 15%. You need to test the paper of your choice. Once you find your amount of dry down you reduce the final exposure by that amount.

Find a set of Fred Pickers news letters all the info you are looking for can be found in then plus a whole lot more.

[Hans Berkhout]

Both the grey disc applied to the back of the lamphousing as well as the thicker diffuser from Meyrick Photographic were recommended by different sources about 20 years ago. I tried the thicker diffuser and it made a little difference, less than I had hoped for. As mentioned above, this can be dealt with through routine edgeburning. Somewhat irritated by Mr. Picker's hype about the perfect product, I finally sold the unit. If you don't believe in a hot spot I would say, like Fred, "try it": focus your neg, remove it, and print for a zone 6 or 7 value. I remember keeping some of these prints to show to fellow photographers, showing both fall-off as well as central hot area.

I all honesty this is a minor problem, I enjoyed using my Zone VI cold light in the Beseler for many years: first with graded papers, later with V.C. The latter I printed split-mode, with a green resp. blue filter mounted in a thin carton frame: just slipped in and out of the filter drawer above the lens.

[d.s.]

Thanks for all the info. Right now I use variable contrast paper so I guess I'll try it out when it arrives and if I have problems printing with VC filters, then I'll see if it can be relamped with a V54 lamp from Aristo. I'd really like a VC head but it's price is out of my range. If I get a V54 lamp, should I get the HI watt model? What kind of printing times should I expect? I don't want times so short that I have to stop way down, and I don't want looonnnnggg exposure times either. Just enough to do a little dodge, burn, ect. Can the lamp intensity knob on the stabilizer be used to control exposure? And would that change the color of the light and affect filter selection?

I tried calling Aristo, and I guess they were closed so I left a message. Besides, you guys are full of information and experience and aren't tring to sell me something so I figure I'll get straight answers and opinions.

Many thanks, dee

[Witold Grabiec]

Dee, Which timer are you actually getting? Is it the Compensating Enlarging Timer or the earlier version? The reason I'm asking is that the Compensating timer gives you a lamp brightness adjustment, which translates to an easy alteration of printing time without changing lens aperture. And it works too.

[d.s.]

Witold, The timer has two knobs, labeled 1 to 100 , and 1 to 10, with a switch below that can be in either a 1/10x or 1x position. plus it has the usual focus/ time switch, power, and expose button.

The power supply has a knob labeled "Intensity" and can be turned from "A" through "L" plus some more lines after the "L". Another knob: labeled "Drydown" has already been explained. There are two lights; A red one that indicates unstabilized, a green light that indicates stabilized. I assume that the photo cell is what tells the red or green light to come on.

I'm wondering if I can use the intensity knob to set the amout of brightness I need for a particular negative, let the thing warm up to a stabilized condition and then turn it from focus to time, then expose at that level of intensity.

I think this is an older unit, not being digital and all. At any rate, When it gets here I'll try it and if I like it, I'll keep it. It may already have a V54 lamp in it. If it dosen't I'll get one.

Dee

[Witold Grabiec]

I'm quite sure the "intensity" knob does allow for just that. The Compensating timer was an upgrade from the "stabilizer and timer" by basically combining the two into one, plus changing approach from the "stabilizing" to a "constant monitoring of light output".

I also found an older copy of Fred Picker's "Zone VI Workshop" and if your head is indeed the one he describes there, then this might be of help too:

the older head was sold with two lamp choices:

- daylight or W-45 for mostly graded papers and higher overall output (shorter exposure times), recommended CC40Y filter for VC papers taped to the negative carrier

- warm light or W-31 (same as V54) for VC papers and no additional filters, except of course VC filters as always, this lamp prints graded papers as well but at longer times

I'd assume that each lamp had an imprint somewhere on it to distinguish the two, so hopefully you'll know right away what you've got.

Either way the head needs about two minutes for warm-up.

[Witold Grabiec]

Dee, In the end I have found Fred Picker's newsletter (supplement to #28, March 1981) that describes the stabilizer you're apparently getting. Without putting it all in here, yet not omitting too much, here is the part that deals with its features: "On the front of the box the are two knobs and a little red and green light. You turn on the enlarger light and let it warm up for a few minutes. Then you turn the stabilizer knob clockwise until red light labelled "unstablizied" goes on. Then you back off slowly until the red light goes off and the green comes on. The green is marked "stabilized". You only have to do that once and then you can leave the knob in that position forever. If, however, you continue to turn the counterclockwise, it will progressively dim the light. More on that later. When the green light is on, it is monitoring the light output continuously and stabilizing it. It is so fast and so accurate, that at the end of an enlarging exposure the green goes off and the red goes on for the blink of an eye. It's telling you the light is unstabilized during the length of time it takes for the light to go from on to off.

...

If you turn the stabilizer knob counterclockwise, past the point where the green light first comes on, you will gradually dim the light. This is an excellent feature because you can now control your printing time without stopping down the lens..."

He then goes on to describe the "dry down" knob, but that has been mostly explained already. If you need info on how to test prints for dry down, let me know and I'll get the rest of it to you.