I'm no scientist Carolyn so I tend to just go by looks, I would never have time to keep up with all the epidermis colors and what color a tomato really is. I take the route of if it looks like a black it is a black. My groups go black/red/yellow/GWR/and bi-color. I stop it there since my customers and I would get really confused if I started labeling based on epidermis color. I can just here the million questions now
I'd also add that so far most every black I have grown has had the same flavor profile, For example Chr. Purple, ISPL, Carbon, and Paul Robeson all taste very similar to me.