cold light and diffusion light

I think we've all said the same thing enough different ways, maybe we can put this one to rest. Regards, ;^D)

I knew nothing about the cold light head, so I thought this would be the perfect venue to learn. Thanks for the responses. Oh, and Mr. Scutter, if you can't contribute an educational response, then please, just don't!

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Originally Posted by David Harritz

This is very nice concept to think about it which is provide such a nice nice information about the thing. It is provide the good amount of awareness about the topic which is being concluded by the you friends. Diffusion lights are very hot in heating the plant which is provide the heater hotness to the plant.

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That's hilarious!

There is a practical consideration which hasn't been raised yet, permit me to do so -

Allowing that cold light and color head/diffusion sources can produce equivalent results, IMHO, a color head can be considerably more cost effective for a new purchase.

A color head (for example, a Super Chromega or a Leitz V35 (a real sweetheart although clearly not LF)) combines a tungsten source, a diffusion box, and a set of dichroic filters in a single unit. It is possible to begin printing on VC papers immediately with a Super Chromega head installed on an enlarger. Color heads of this type are readily available used (the usual web auction place) for relatively low cost. If your work genuinely requires a #5 grade paper, dial all of the filters to "0" and use a #5 VC filter beneath the lens.

Garden variety cold light heads, nice as they are, have an emission spectrum that is not a good fit with VC papers. There are purpose-designed cold light heads intended for use with VC papers but these cost vastly more than the simpler units.

Certainly the quartz halogen bulbs required by the common color heads are somewhat pricey (shop around though, there are bargains to be had) but one can buy very many of these bulbs for the cost of a variable contrast cold light source, at least the Aristo type. The cold light source tubes will eventually fail, and I'd wager that the quartz halogen bulbs used in the dichroic color heads will be available some time after the Aristo bulbs (tubes really) are a memory.

Your mileage may vary; I expect the Super Chromega D on my D5 (and my stash of bulbs) to easily outlast me.

Good light all-

Although there may not be any difference in the way light is diffused through a cold light vs. diffusion source such as from a dichroic color head there is a difference in the light itself. It has always been my understanding that a cold light head produces light that is more actinic but correct me if I'm wrong. This would explain why my print exposure times are shorter with my Zone VI cold light in comparison to the exposure times when using using a diffusion head illuminated by quartz halogen. As for the end results in print quality I doubt you would see any significant difference between the two diffusion sources.

I currently use an Oriental VC CLS head which I really like. Once the tubes go out I guess I will have to go back to my Zone VI head or my Beseler 45S color head because as I understand it there are no replacements.

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Originally Posted by Raven Garrow

I was wondering what the benefits are using a cold light source over diffusion.

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Simple answer, 3 reasons:

Less heat for a given intensity. No need for a fan. Less expensive when new (Aristo 1414 = $700 in 1988, Durst CLS1840 = $24,000 in 1988)