On Biola Film 2007, "Mujo no Kaze" [The Winds of Impermanence], I was in charge of several effects. One was smoke, the other was blood. Here are the test photos:
The cigarettes had to be herbal--didn't want our actors getting hooked. But I wanted to be thorough and make sure that the herbal cigs I bought would show up as well onscreen--and they passed with flying colors. As this picture shows, it's all in the lighting.
This blood is a slightly better formula than the stage blood you usually see. Red dye, corn syrup, corn starch, water, blue dye. Kodak photo-flo, milk and black ink can be mixed in, depending on the application. Photo-flo is toxic, and ink isn't all that good for you either. Zinc oxide can be substituted for the corn starch--looks a bit better, but not as easy to acquire.
Here's the ideal mixture:
1 oz water
1/2 tbsp zinc oxide/corn starch
1 pint white corn syrup
1 oz red food dye
2-3 drops blue/green food dye
1 oz kodak photo flow [if this is used, mixture is now toxic.]
1 tsp milk
Funny side-note: I didn't have any chalk on-hand. The 'chalk' outline is actually baby powder. Works well enough for a test, [chuckle] but I'd get real chalk for the movie.