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Ultraviolet tubes in Kinos


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#1 andrew ward

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Posted 08 March 2013 - 03:01 AM

Was thinking of getting some uv tubes for Kinos but in searching the forum i read some alarming safety warnings.
I believe having uv (blacklight) bulbs on set is similar to being in the sun, anyone know if thats true or is it worse?

And anyone know why your vision goes blurru when you look at uv tubes?

Also would 4 tubes (in a Fatman Kino) be enough to shoot midshots of a subject with uv bodypaint? Im thinking 4 or 8 should be enough (no other lighting in scene (unless some hmi with Congo Blue style fill would sell the gag more).

Ta
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#2 Keith Walters

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Posted 08 March 2013 - 04:25 AM

Was thinking of getting some uv tubes for Kinos but in searching the forum i read some alarming safety warnings.
I believe having uv (blacklight) bulbs on set is similar to being in the sun, anyone know if thats true or is it worse?

And anyone know why your vision goes blurru when you look at uv tubes?

Also would 4 tubes (in a Fatman Kino) be enough to shoot midshots of a subject with uv bodypaint? Im thinking 4 or 8 should be enough (no other lighting in scene (unless some hmi with Congo Blue style fill would sell the gag more).

Ta

It depends on the type of tube.

 

All types of the tubes contain low-pressure mercury vapour  which produces UV light when a current passes through it. In an ordinary lighting tube, a fluorescent coating inside the glass tube converts most of the UV into visible light. The tube is ordinary soda glass which is transparent to visible light, but absorbs most of the dangerous UV wavelengths.

 

Black party-type UV fluorescents have the same ordinary soda-glass envelopes but with a dark tint that absorbs most of the visible light and lets through some of  the harmless long-wavelength UV, and no fluorescent coating. They're perfectly safe.

 

The clear type that are used in tanning beds etc have more expensive quartz-glass envelopes that allow the short-wave UV through, and they are much more dangerous, requiring safety goggles. Also not too useful for filming applications as they allow  lots of visible bluish light through as well. That's not essential to their operation, but it ensures people don't mistake them for party type fluoro's.

 

Your vision does sort of go blurry, but that's because your eyes have very poor resolution at blue wavelengths.

 

You also need to find blacklight tubes with a power rating that matches the kino flo ballasts.


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#3 Toby Orzano

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Posted 08 March 2013 - 10:31 PM

Your rental house should be able to help you out with the correct tubes for Kino fixtures. Also of note: Altman makes some UV broadlight units, from what I recall they were 400w. This is not equivalent to 400w tungsten, UV reflective surfaces illuminate much brighter than a 400w tungsten would illuminate any normal objects.


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#4 andrew ward

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Posted 09 March 2013 - 02:16 AM

Love your works!
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