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Thread: Cold lite?

  1. #1
    ronlamarsh's Avatar
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    Cold lite?

    I have a V54 aristo cold lite, how can you tell when the bulb needs replacement?
    No escaping it!
    I must step on fallen leaves
    to take this path

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    Ken Nadvornick's Avatar
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    Louise Kessler from Voltarc/LCD (Aristo) has given the following guidelines in post #23 from this thread:

    "...the nanometer output of the given lamp will change over time. The more the lamp is used, the more it will age and the phosphor will degrade. The strongest output of any lamps will be in the 1st hundred hours of its use. After this time it goes into its "median age" - think of a bell curve and it will slowly go down in strength. Replacement of the lamps on the down side of the curve is dependent of the photographer and how much he’s willing to lengthen his timing to compensate for the lamps aging.

    "Usually at the end of a lamp’s life the nanometer output and its ability to make the chemical reaction is very low. The lamp has a harder time to recover from exposure to exposure. The lamp is basically telling you that it’s done and will shortly - electrically die."

    She was originally discussing the Aristo VCL variable-contrast dual-tube lamps but her above comments, as she states, should apply to any of the Aristo lamps.

    Ken
    "They are the proof that something was there and no longer is. Like a stain. And the stillness of them is boggling. You can turn away but when you come back they’ll still be there looking at you."

    — Diane Arbus, March 15, 1971, in response to a request for a brief statement about photographs

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    ic-racer's Avatar
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    When you turn it on and it no longer lights up

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    RalphLambrecht's Avatar
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    Why anybody puts up with the idiosyncrasies of this type of lighting is beyond me.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

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    What do you use Ralph? I don't have your books.

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    RalphLambrecht's Avatar
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    Dave

    That's my point. It doesn't matter. Diffusion, condensor or whatever enlarger, all one has to do is process the negatives accordingly. There is no inherent quality difference with one or another type of light source. If that's agreed (the evidence is proven by contemporary literature), the optimum light source is one that is consistent and flexible in changing contrast. This typically leads to diffusion color heads or condensor enlargers with under-the-lens filtration. Considering the above, I don't see why cold-light heads are so popular in the US. They offer no quality advantage over other light sources, but have a few disadvantages in the areas of consistency, repeatability and convenience that would drive me nuts.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

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    Thanks Ralph.

    Perhaps that is why I've had a hard time deciding which head I like best on my enlarger. I use an old Omega D2 that came with a condenser head and I later picked up an Omegalite head that uses a circular fluorescent bulb. I tend to use that head most because I feel it might be better for various film formats since my enlarger does not have the variable condensers. I experimented with different fluorescent bulbs and found one that seems to work well with my negatives. I've stayed with that setup for years now.

    Dave

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    RalphLambrecht's Avatar
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    Dave

    You matched your light source with your typical negative contrast, which is just fine. Others may have to change film processing to adjust their negative contrast to match their light sources, and that's reasonable too. However, running out to spend a ton of money to change a light source in hopes of fixing the underlying problem of inappropriate negative contrast, is not advisable. This is especially true for cold-light heads, because I believe, they fix one problem and replace it with a few others.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  9. #9

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    Quote Originally Posted by RalphLambrecht View Post
    Dave

    That's my point. It doesn't matter. Diffusion, condensor or whatever enlarger, all one has to do is process the negatives accordingly. There is no inherent quality difference with one or another type of light source. If that's agreed (the evidence is proven by contemporary literature), the optimum light source is one that is consistent and flexible in changing contrast. This typically leads to diffusion color heads or condensor enlargers with under-the-lens filtration. Considering the above, I don't see why cold-light heads are so popular in the US. They offer no quality advantage over other light sources, but have a few disadvantages in the areas of consistency, repeatability and convenience that would drive me nuts.
    Thank you. That's just what I learned first hand When I picked up a Beseler 45 With an Aristo lamp. I was thinking about replacing the tube with something more compatible with VC papers. Not worth the expense considering all the other crap you need to deal with. Sold the Aristo unit and got a condenser lamp house for the enlarger. Works like a charm, but I still prefer the dichro head on my Omega D4.
    Frank Schifano

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    Ken Nadvornick's Avatar
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    Everyone has their own experiences and preferences. I've used both the OEM condensers and third-party fluorescent cold lights in my Omega D5XL. Each has certain advantages and disadvantages over the other.

    The sum of my own experiences led me to prefer the cold lights for black-and-white work. When the equipment is working properly, I find the cold light heads to produce consistent, repeatable output which I find very convenient to work with.

    I can work out the formula for a print using fresh chemistry, make one, then shut everything down and leave it all for a week. When I return I can set out new fresh chemistry from the same stock, then precisely repeat the formula and obtain an exact duplicate of the original print on the first try. I've done this before, more than once. Can't get more consistent or repeatable than that.

    The key, of course, is not the light source. All of these are prone to drift for various reasons. The key is using closed-loop control systems to manage that drift. I utilize several in my darkroom. Together these serve to remove a sizeable amount of the unexplained background "voodoo" that used to drive me nuts. ("What happened? I know I did everything exactly the same! Why is this different?")

    But like most things in life, there are usually several ways to skin a cat. Cold light versus non-cold light is no different. Youz pays yer money, and youz takes yer chances...

    Ken
    "They are the proof that something was there and no longer is. Like a stain. And the stillness of them is boggling. You can turn away but when you come back they’ll still be there looking at you."

    — Diane Arbus, March 15, 1971, in response to a request for a brief statement about photographs

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