The red one should fire to black, and the black one to red. The grey one is meant to turn green, and the cream/buff ones might variously change into blue, lavenders and grey.
There are doubts about this: I’ve never tried any of these before. What’s more, since I only have old kitchen scales for the ingredients*, the oxide components for a test batch are unmeasurably small. 4 grams, possibly, but half a gram? One tenth of a gram? You’re kidding, right? I am still back in the realm of smidgens and pugils.
And I hope I got my labels right.
*£60 for scales which weigh in 0.1g increments, that’s why.