Ways of making coloured muzzle flashes in films

[MoviePropMaster2008]

Japan has prohibited firearms ownership for generations. Most of the Japanese films I've seen have 'flash paper' fake firearms (like the 'crime saga's of the 1970s-1990s). Kurosawa's RAN used actual Matchlock muskets and there is a special low powered black powder charge that looks 'pink' or 'magenta' when fired. I use low powered black powder charges and they have a definite 'pink' hue to the flash. But most of the Japanese cinema uses proprietary 'flash paper' guns.

I have never seen other colors in use (doesn't mean they don't exist but I haven't seen them). Most of the color variations are because they aren't using real firearms. Case in point: "the acetylene 'uzi' used in "The Osterman Weekend" had a very 'odd' color to the muzzle flash. What's weird that in the movie, when the assassin removes the 'magazine' from the gun, we see a flame flash out of the mag well, very strange looking! Wow, what a weird gun and back then, they thought it would replace real firearms, but those 'non traditional' solutions for having to fire real blanks never caught on.

No one ever stopped anyone from using various chemical to get colored flashes, but ultimately it's too expensive and too much of a hassle now, especially since we can change the color in post production. Just remember too, some chemical compounds to make weird colors are CORROSIVE and thus people don't want them in their blanks.

[Mazryonh]

Thanks for the information about Ran and its pinkish muzzle flashes. Which pyrotechnic colouring chemicals are corrosive, exactly?

As a concrete example, the Chiappa Rhino 50DS used by Kate Beckinsdale from Total Recall (2012) had blue muzzle flashes (even though every other firearm in that film had conventional muzzle flashes). Let's suppose that, instead of relying on digital post-processing to turn muzzle flashes blue, they used special chemicals in the blanks. Wikipedia claims that the chemicals to make flames turn blue are copper-based, which shouldn't normally be corrosive, otherwise leftover copper from jacketed bullets would corrode gun barrels. Just how much more expensive would it be to use those chemicals?

There are times when CGI muzzle flashes don't really cut it. If it's an indoor area or a scene where there are walls or similar environmental objects close to the gun being fired, those objects usually won't light up with the muzzle flash (because lighting up the area with the properly-coloured light or doing so via CGI needs more out of a budget), which is fairly noticeable. Of course, if the background itself is largely CGI, such as in the Star Wars prequels, then it's easier to get the needed "environmental lighting" with CGI.