I think the color comes from how much oxidation has occurred in your raws. Darker color = more oxidation = less tren. Kinda like how rust forms on metal. I also could be 100% wrong, I dont know too much about chemistry lol. I’d assume carrier oil also plays a role in what color your finished product is gonna look like.
Got no solid answer to you question. BUT the best tren ace I’ve ran was more amber colored. Came with all the demons, all the sides, all the cough and all the tren mightyness. Currently running some piss looking tren which is good too, but not I’ll end up in prison good. Can’t judge it by the color.