Flash paper is a particular form of nitrocellulose
. Specifically, it is nitrocellulose that has been formed into thin, flat sheets and dried. When in this state, it can be manipulated like normal cellulose-base paper - i.e., folded, spindled and mutilated
. However, when it is ignite
d, it burns very rapidly with a bright light, leaving almost no residue
. For this reason, it is popular with stage performers (especially illusionists
) who use it to create distractions. Because it burns so quickly, small sheets can be handled with unprotected fingers while burning to destruction, which produces the illusion of bright flashes or flames appearing from the fingertips.
It is made by treating cellulose base, or ordinary paper pulp, with concentrated nitric acid (HNO3) to produce nitrocellulose and water as follows:
C6H1005 + 2HNO3 -> C6H8(NO2)s05 + 2H20
Typically, this process is carried out with the addition of sulfuric acid (H2S04) in the mix. The sulfuric acid will react with the water and bind it, preventing it from diluting the nitric acid being used in the primary reaction. Once the nitrocellulose base has been formed, it is washed to halt the reaction then dried slowly and carefully at low temperatures. It is an unstable substance when dry; shock and heat will cause it to decompose (burn). For this reason, it is typically stored and shipped damp in sealed packets.
Flash paper is useful to other professions than stagecraft. Espionage favored it for a time as well; it was handy for writing down information that might have to be destroyed quickly and completely in the event of compromise. The most popular use was for the construction of 'one-time pad' ciphers, where the capture of the pad would be a severe setback but its construction (many sheets tightly packed) made destruction by burning difficult. In the modern world, however, it can be more trouble than it's worth, what with air travel, chemical sensors, and the like!
Flash paper is, essentially, chemically identical to both guncotton (a favorite explosive of Jules Verne) and early motion picture film stock. Early movies were projected from 'nitrate film' or 'celluloid' which was, essentially, nitrocellulose with photochemicals bound to it - which is why old movie prints are an explosive hazard.
If you want to play with flash paper, do yourself a favor. Don't try to make it. It's easily, cheaply and safely available from your nearest stage magic supply house, usually in the form of 'pads' that look somewhat like post-it notes. Today, it is used not only for hands-on illusion but in all manner of pyrotechnic effects such as wands, flashpots, and so on. It is used as an igniter for more spectacular substances in larger effects, due to its ease of ignition.
WARNING! Flash paper is a PYROTECHNIC. As such, it can cause uncontrolled fires and can burn you if you don't know what you're doing - or even if you do but get unlucky. Exercise extreme caution when using it, and make sure you've been trained to handle pyrotechnic devices!