Flash powder for photography

[djjudas21]

Hope this is the right place for this question. I'm a photographer who uses traditional equipment and darkroom techniques. One of my cameras dates back to 1886 and I want to start using flash powder for full authenticity.

 

I'm not sure if photographic flash powder is exactly the same as pyro flash powder, as the photographic type is designed to be as quiet and smokeless as possible, and emit as much light as possible. The recipe I found for photographic flash powder is 5 parts magnesium to 1 part potassium nitrate. I mixed in this proportion and in total I made 0.5g of flash powder. By experimentation I reckon 0.1g gives a bright flash that is comparable to a powerful modern-day electronic flash.

 

However I had problems igniting the powder. Having read about its volatility, I tried using a spark lighter for a gas oven - nothing. Then I tried to use a flame lighter (basically a cigarette lighter with a long handle) - nothing. Finally I used a small blowtorch and after a few seconds of heat, it ignited. Sparking up a blowtorch is clearly impractical for photography so I was wondering if there's an easier way of lighting it. I'm sure the olden-day flash pans had either flintwheels or a match on a lever, like a matchlock rifle.

 

I also considered some kind of system with batteries and a wire filament.

 

Does anyone have any thoughts about using slow-burning flash powder for photography?

 

Thanks,

Jonathan

 

[Bobosan]

Hello Jonathan and welcome. If you are reproducing photoflash as used waaaay back in the day, might try a few of the "safer" formulas listed as "photoflash" below.

 

Photoflash
Source: Kirk-Otthmer chemical encyclopedia[8]. Chapter 'Explosives and Propellants'.
Comments: Heat of reaction: 8.989 kJ/g, Gas volume: 15 cm3/g, ignition temperature: 700°C, impact sensitivity test: 26% of TNT. half a pound of this flash delivers 120 million candlepowder. It is used in the M120A1 and M112A1 flare cartdriges.

Preparation:
Aluminum (20 micron; atomized)....................40
Potassium perchlorate (24 micron).................30
Barium nitrate (150 micron).......................30


Source: rec.pyrotechnics. Post by Bill Nelson <billn@hpcvaac.cv.hp.com. Composition from Allen’s book.
Comments: This is a relatively safe flash composition. Burns with a brilliant white light in an open tube, or when unconfined. When well confined, it produces a loud, low pitched report and a short but intense flash.

Preparation:
Potassium nitrate.................................50
Sulfur............................................30
Aluminum..........................................20


This formula produces a very
bright flash. This formula is what use
to be used for the photo flash for the
old box type cameras about 100 years ago

Barium Nitrate 3 oz.
Potassium Perchlorate 3 oz.
Aluminum Powder 400 Mesh 4 oz.

[djjudas21]

Thanks for the helpful info. Are these photoflash recipes easier to ignite? i.e. won't require a butane torch?

[Bobosan]

I've never tried these so don't know. First formula states 700C ignition (about 1300F). Second formula with sulfur may ignite at lower temps.

[Mumbles]

The first and third formulas are the same, and are also listed in Ellern. They probably wont light particularly easily, due to using spherical aluminum. The second one I can speak from experience lights relatively easily if using any manner of flake aluminum.

 

You can find a number of photoflash formulas here: http://www.oocities.org/wdb_0wnz_j00/flash_top.html#Photoflash%20I The more dangerous ones are listed in red and orange. I'd avoid them.

[Bobosan]

Yup, I purposely avoided the chlorate based flashes because of the risks.

[Mumbles]

If you do some digging into this, you'll probably find some conflicting information. The term "photoflash" will probably be used in more than one way. Obviously the way you're intending and interested in is the original. The more common usage is going to be related either to a military/police device, or a certain type of shell. The military/police device might also be called a flash bang and is used to disorient and distract targets. The shell type is usually a shell of photoflash inserts which display a bright flash with little to no sound. The other two usages depend probably just as much on construction as formula.