Flash powder

Michel Hardy-Vallée

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The carbon arc lamp was popular for many years as they could remain lit for hours. In fact, they are still used in some places for lighting large areas for photography.

PE

I heard they had the interesting side-effect of generating a ton of UV light, thereby slowly disintegrating the retinas of the talent lit with it.

Also of interest to the discussion are flash sheets. They were sheets of quickly flamable substances that were lit in a special holder.

The sheets:
http://www.nwmangum.com/Kodak/FSheets-1.html

The holder:
http://www.nwmangum.com/Kodak/FSH-1.html
 

Larry.Manuel

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Carbon arc lamps: beware, there's a lot of UV emitted, and your eyes won't feel any pain, but can become badly burned.

As I understand, flash powder was composed partially of calcium oxide. Some reaction heated it to incandescence. Hence the word limelights for theatre footlights, which, I assume, had some system of injecting a steady flow of calcium oxide into or near a gas flame.
 

snallan

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Hence the word limelights for theatre footlights, which, I assume, had some system of injecting a steady flow of calcium oxide into or near a gas flame.

Limelight was generated by heating a block of calcium oxide (Lime) using a hydrogen/oxygen flame. The light generated was a mixture of simple incandescence, and candoluminescence. That is the emission of light from the lime due to electrons that have been promoted to higher energy levels within the atomic structure, falling back to their base energy level, the energy being released in the visible spectrum. Thus the light is much brighter than would be expected simply from heating the lime to white heat.
 

bsdunek

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Carbon arc lamps: beware, there's a lot of UV emitted, and your eyes won't feel any pain, but can become badly burned.

Yes! It's the same as watching an arc welder without protection. You can 'sunburn' your eyes, and that is very painful. There will be permenent damage to the retina too.
 

Aurum

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Good old arc-eye. Not a character from MASH, but bloody uncomfortable, like having a lump of grit in your eye. Got mine by being slack with the welding mask when MIG Welding the Landrover.
As an aside electric arcs do generate enough UV when using them close up to give you a dose of sunburn. I'd reckon 20-30 minutes continuous in front of the torch=couple of hours on the beach without sunblock.

Toasteeeeee!
 

Larry.Manuel

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http://www.xs4all.nl/~lommen9/index.html [below: excerpt from the page]

San Francisco News
PHOTOGRAPHER HURT BY BLAST.

October 17th 1930

Accidental explosion of a bottle of flashlight powder injured George Sheldon Examiner photographer just at the close of the reception to William Randolph Hearst in the rotunda of the city Hall yesterday noon. Sheldon's right hand was badly lacerated. Several judges and city officials seated nearby received slight cuts and burns
 

holmburgers

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Terence

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Seriously, if you want to know about old flash techniques, THIS is your resource.

Now I totally want to experiment with flash photography, just to try using something called "Bengal fire" . . .

I could have sworn that's what I got after my last visit to the local East Indian restaurant . . . seemed flammable enough.
 

JPD

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Magnesium powder and potassium nitrate works, but never use it indoors! Burning metal particles flying around aren't fun. Hey, I got some in my face, and luckily just had to buy new eyeglasses after my last experiment. New eyes can't be bought.
 

Denis R

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found via google books while searching for acetone...

tucked away in wilson's photographic magazine from Jan. 1906

found this little gem:


now to actually find the book.....
 
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George Sheldon was my father, at his death he was the Photographic Editor of the SF Examiner . . .
 
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