Maurice Ribble of Tech Photo Blog recently found the ingredients list for flash powder, which was used for state-of-the-art photographic lighting 150 years ago. After making some of the powder, he began to test it to see how it compares to modern day flashes (more specifically, a Canon 580EX II).
One of the tests is a simple scene that was lighted with a modern flash and then flash powder so we can compare the images. Overall I was quite impressed with the amount of light that even a small amount of flash powder makes; however, there were many disadvantages to flash powder.
If you’re interested in making your own, a simple search on Google will point you in the right direction. Be careful though — the stuff is quite dangerous.