I see a lot of purples on this thread that are red purple in my climate. In my experience, the more sun and the higher the temps, the more likely purples will show red tones. Also, most digital cameras and phone cameras add blue tones to photos that make them look like truer purples.
The truest Northern purples I grow are Emmerichs:
Faith that Moves Mountains
Soli deo Gloria (94-degree day)
Reckless Girls is close to a true purple when night temps are 70 or below.
Some of my Southern purples and seedlings stay looking truer purple even when temps are in the 90s.
Midnight Castle
Jeanne Deaver's Dream
I have three seedlings that keep their true purple colors in the late season heat:
