About the subject of blue stars with KNO3...
I found an old book with some even older compositions.
When reading it I found many recepies with S and KClO3, and others with "sulfur copper" and similar trivial names...
To the subject. I found a star named "Blueish" or similar translated in to english. It contains 2 parts "powder BP" and 2 parts "granulated zink".
I have not tried it, but might be interesting for anyone without access to proper chemicals to make more modern blue stars.
You know, I was thinking the other day about those dangerous old comps. There is a way to "safe" almost anything, that's used in the drug industry.
They coat drugs as micron sized pellets, with coatings so passive they can determine how long it will take or in what part of the intestine they will dissolve.
Similar tech applied to pyro chemicals, using waterproof passive coatings would make almost any mix safe. The coating would burn off and the comp would actually be "mixed" as it burned.
Given the way pyrotechnics is the unwanted stepchild of the chemical industry, it will probably be fifty years before anyone applies this technology to pyro chemicals. Sigh.
Imagine fine sulfur coated with chlorine doners, or whatever else you needed to make the color bright. Or imagine two or three coatings, meant to burn off as the particles were shed, to give stars with one color at the center of the flame, another color at the outside. Or whatever else you can imagine - stars that sparkle on the outside or leave a dark trail that crackles and flashes three seconds after the star passes. Great possibilities.