Carbon Arc Photometrics

30th January 2004

Hello All,

Working on an art installation that's using a bare Carbon Arc flame.

I was wondering if anyone by chance had experience running brute arcs with clear lenses. I need photometric data to help with the early design. Any advise would be greatly appreciated.

Best,

Erik Messerschmidt
DP • Gaffer
Los Angeles

Erik Messerschmidt writes :

>Working on an art installation that's using a bare Carbon Arc flame.

I may still have this info somewhere, I'll try to look for it over the next couple of days when the turkey OD whereas off.

Meantime you should be aware that an open carbon arc produces a tremendous amount of ultraviolet light much like arc welding.

So much so that clear carbon arcs are used for accelerated fade testing of color dyes and anything else that is supposed to be sunlight resistant -- paints, sails, electric cables, etc.

It is extremely easy to get burns on your retina as well as any exposed skin.

Be very careful.

Brian Heller
IA 600 DP

>Meantime you should be aware that an open carbon arc produces a >tremendous amount of ultraviolet light much like arc welding.

Much aware, thanks Brian.

We're having a UV coated Pyrex glass shield built to surround the arc. The audience will also be protected from direct light by an opaque shield.

What I'm specifically interested in is the photometric data associated with a bare flame sans reflector and lens. It's hard to find but was thinking someone might have done this before. I'm trying to gather as much info as possible before I march down to Mole-Richardson with my meter so anything you can dig up would be greatly appreciated.

Thanks

Erik Messerschmidt
DP • Gaffer
Los Angeles

Erik Messerschmidt writes:

>What I'm specifically interested in is the photometric data associated >with a bare flame sans reflector and lens.

The only thing I could find was an old flyer from the Atlas Company in Chicago.

It describes their "enclosed carbon arc" testing devices. I believe they are still in business, but not sure if they still manufacture carbon arc devices.

There must be a lot of data on carbon arc characteristics available from materials testing research.

Maybe someone at Atlas can help. I believe Union Carbide acquired the National Carbon Company which was the manufacturer of most carbons used in the US. If you do go to M-R, I'm sure Peter Mole could tell a great deal more.

You might also try the SMPTE in NY and the American Society for Testing and Materials.

Brian Heller
IA 600 DP

I'm not sure if this has what you're looking for, but here's a URL for the National Projector Carbon Bulletins (1957-1960?). I think Bulletins 1 and 2 may be most useful.

http://www.film-tech.com/manuals/CARBONBULLETINS.pdf

If this URL doesn't work, visit film-tech.com click on Manuals, scroll down to Miscellaneous, and click on National Carbon bulletins.

Jeffry L. Johnson
Cleveland, Ohio
Projectionist, Great Lakes Science Center OMNIMAX Theatre
http://www.glsc.org/omnitech.html

Erik Messerschmidt writes :

>Working on an art installation that's using a bare Carbon Arc flame.

The Handbook of the Illuminating Engineering Society has a great deal of info on carbon arcs that may be what you're looking for; it also has an excellent list of references.

Brian Heller
IA 600 DP