Old Press Cameras with Flash Powder

[Nathan Potter]

As Ole says using pure magnesium is relatively safe because no oxidizing agent is present. The trick is getting enough heat to ignite it and to ignite it quickly. It'll burn white at I believe somewhere around 5000 degrees Kelvin.

Other versions of flash powder can use aluminum or magnesium as the fuel and an oxidizing agent as a hefty source of oxygen. These can be extremely dangerous because they are an explosive! This is especially true if they are percussive - that is they can explode on sharp contact without heat (the sharp contact can generate enough heat). Using potassium permanganate, ammonium nitrate or potassium chlorate as an oxidizer with the aluminum or magnesium is in this catagory of percussive mixtures. Due to the oxidizer additive and some other constituents the burn color of the oxidizer flash powder is somewhat lower in color temperature than pure metal versions. I believe the version using ammonium nitrate with aluminum dust was used as the high explosive called "Amitol" during the first world war.

Nate Potter, Austin TX.

[Ernest Purdum]

Regarding the hazards of magnesium, I am reminded of an incident which tied up a Southern California freeway for hours. A magnesium bar fell of a truck. It lay there for hours until an explosives contractor was hired to take it away. A solid bar of magnesium is no hazard at all. A high school friend of mine ground away on a piece of magnesium for a long time with no ill effects at all. When, however, another kid attempted to sharpen a screwdriver, the slightest touch to the wheel lit up the whole shop. Fortunately, neither he nor anyone else was injured, but he sure was startled. Magnesium dust is redily flammable, solid magnesium is not (early Volkswagens had several large magnesium castings).

In my youth I occasionally used Kodak flash sheets which were made, I think, of sintered magnesium.

[Eric Woodbury]

Burning magnesium is a problem because it cannot be extinguished with water. It will burn under water. Sometimes it is machined (in machine shops). I believe it actually an alloy that cuts better than pure and burns less. Still, there is always a CO2 fire extinguisher present. In the 60s and 70s, printing plates were sometimes made of magnesium instead of zinc. My father would bring them home and I would try to burn them in the fireplace. They had something mixed with them and they didn't burn that well. Pure ribbon, however, can be ignited with a match and can be used to set off a thermite reaction (aluminum and iron oxide).

A friend of mine used flash powder in the 30s. He told me that if he used it inside, he only got one pic because of all the lingering smoke.

[Colin Corneau]

I just bought a Crown Graphic with the flash attachment, complete with all wires, etc. (trivia note: the original 'light sabres' used in the Star Wars movies were the handles for these flashes) recently. It even came with the flash bulbs, too.

I got two, in fact. I highly doubt I'll ever use it -- if you're eager to pursue this, and don't want to blow yourself up with magnesium powder, I'd look for one of these things used.

[alec4444]

Thanks for the responses, guys. Agreed it would only be useful indoors as it seems that the intended effect would be to bounce that light off of a ceiling. (Did they ever direct light forward??)

Still intrigued. There must be less-hazardous forms of flash powder to burn.... The power of the flash might be different, as with the color temp, but I imagine the same concept could be applied with better safety. Finding a powder that can be measured with a flash meter and consistently applied (I liked the story of Ansel using too much) should be easier these days...

A (rather quick, I admit) search of eBay with the term "Graphic" in cameras & photography yielded no results as I could see that included this old style of flash. Lots of flashes with bulbs, but none of the powder based flashes. Of course, having not seen one I'm not entirely sure what I'm looking for. If someone has one I'd be thrilled if you posted a picture!

The concept of shooting one of these things is nestled in-between some other somewhat absurd fantasies I have, including shooting a cirkut camera or buying and resurrecting one of those old tintype cameras with the instant development tray built into the camera. So many things to explore, so little time & money!

Cheers!
--A

[Ole Tjugen]

The flashbulb was invented in 1928, so only the first "top handle" and some "pre-anniversary" Speed Graphics would have been used with flash powder. A flashbulb is so much safer and repeatable than flash powder that the switch was almost instantaneous once the flashbulb was introduced in the US in 1930.

"Less hazardous flash powder" is not very likely: It needs to burn very rapidly with a high light output, meaning high temperature. Fast and hot don't mix well with safety. MAgnesium ribbon, as I've mentioned previously, is probably the closest thing you can find to "safe".

[John Schneider]

Burning magnesium is a problem because it cannot be extinguished with water. It will burn under water. Sometimes it is machined (in machine shops).

Magnesium not only cannot be extinguished with water, water will make the problem worse (as in exploding):
Mg (s) + 2 H2O (g) → Mg(OH)2 (s) + H2 (g)

The gaseous H2 will of course explosively combine with atmospheric oxygen. Dry sand is the preferred way to put out a mag fire.

Apache helicopter tailrotor gearboxes are made from a magnesium casting, and I've seen the aftermath of a mag fire on a milling machine, after a coolant pump broke. The damage was spectacular.

[Joseph O'Neil]

Theatre supply companies used to sell flash power, used in "flash pots" for live theatre, but it has been years since I checked if it was still for sale. It was basically the same stuff.

However, I too have seen magnesium burn. Unless you are sure of yourself, you do NOT want to fool around with magnesium. Also, for what it is worth, if you do use the stuff, do so only outdoors, not inside. I know several guys who do historical re-enactments (War of 1812, Civil War, etc), and they always, always, always fire off their muskets outside due to the smoke, allergies, flying hot bits of powder, and so forth.

Also, it might be more fun or interesting to shoot a photo using a lfash tray at some sort of historical re-enactment. In fact, I vaguely remember somebody doing that sort of thing many moons ago, but I forget their name now. Something to look into

joe

[BrianShaw]

I don't think Jacob Riis is available to provide input, but maybe tracking down this kid from San Diego would be interesting:

http://www.npr.org/templates/story/s...oryId=92042960

[goamules]

Alec4444,
There is a nice guy named Race Gentry on the CW Reenactors collodion forum that has used the period flash trays a lot. He was even interviewed on NPR. I recall seeing some MPEG movies he posted showing the flashes in operation. Do a little searching and you should find him. It's totally do-able.

Update: just found a link with the movie:
http://www.cwreenactors.com/phorum/read.php?1,3371

Garett