Scientific Peacemaker Color Theory
We see Peacemaker glow different colors when wielded by an Earp(ish) and pointed towards a revenant, demon, resurrected witch, whatever Bulshar is, - a bad guy. So apparently we need these two parameters in order for this reaction to take place.
I present that this is because Peacemaker’s barrel is basically a gas discharge lamp by way of hot cathode vacuum tube.
This type of set up needs a filament to heat up the gas within the vacuum in order for it to emit (colored) light. We see little spirally lines within the barrel in one of the really cool shots early on in the series - that’s definitely the filament and it’s powered by Wynonna (or the wielder) through her electrostatic current from being the heir - and super electric and magnetic, am i right? (it’s one of her superpowers, okay, let’s not dwell too long on how that works, it just does).
The vacuum in the barrel is created because it’s the gateway to the portal of hell and since we see people being sucked in, we can assume it’s definitely a vacuum down there.
Okay, so we have half of the process down but now how do we account for the different colors? Easy, each person put down by Peacemaker emits different atoms based on their past lives. It’s a curse, just go with it.
Orange = Sodium. Totally obvious right? When the atoms of sodium are excited and ionized, they produce an orange light. What’s more is that sodium is mainly found in the earth’s crust - which just happens to be where revenants and other demons are pulled through on their journey to hell. Want more proof? Sodium ignites when in contact with water and we see flames accompanying the hole in the ground and let’s face it, there’s always some type of moisture on the ground in Canada. (Right? Asking for a Texan friend)
Blue = Carbon Dioxide. CO2 emits a blue light when ionized/excited and this also makes sense since Rosita and Willa were the most ‘human’ and they were super into nature, where carbon dioxide is plentiful. Plus the Stone Witch was basically a lump of carbon when she went down.
White = Xenon. Xenon is super rare. Like super duper have to go to the center of the earth rare. If hell is down below, then who would have been the furthest down there and therefore carrying around the most xenon? Bulshar. Plus, he’s extremely rare. Let’s hope.
https://en.wikipedia.org/wiki/Gas-discharge_lamp
https://www.youtube.com/watch?v=CLpNeBStCUY&t=269s&ab_channel=Nerdist