I went through the purple craze for about a minute and then I moved on. I used the genetics that had purple for other things. In fact I spent a few years with a cross of PCK "A very colorful strain" while isolating the green pheno and working out the purple. Years later I have an IBL cross of PCK and Durban that is entirely green and much more potent than the purple expression that's predominate in PCK. The green PCK pheno is less common than the purple but it's so much better.
Most people use PCK to bring in the purple but when I first grew it I had one that was green. After harvest I realized the green was much superior so I started more seeds looking for another green pheno to use for a cross. I found one but the purple was still showing up in the crosses. Worked to the F8 generation and no more purple. Just skunkiness. Last run was 100% green weed and that was what I wanted.
A true purple plant will have purple buds and green leaves. All this cold temp nonsense is just bullshit and a waste of time.
I find it to be completely ridiculous the lengths people go to for some stupid purple weed. All you have to do is grow weed that's purple regardless of temperature or some other ridiculous method to induce the color.
I hate purple weed but I've grown lots of it and I never did anything to make it turn purple.