I said this in another thread just today...but I'll say it here, too...because not everyone reads every thread. :P
The term "black back" is nothing more than a descriptive term that describes a particular pattern trait. It is NOT a genetic term in the same way that "pastel" or "cinny" are.
When Corey Woods first told his story about the Het Red Axanthics and Red Axanthics, he says he was breeding together two "black backs" in hopes of proving that the trait was inheritable and producing more black backed babies. Instead, he made the surprise discovery of a super form and named it Red Axanthic. Because the founding stock were het for the super form, he named them Het Red Axanthics.
Just because the Het Reds had the black back trait does NOT mean that all black backs are Het Reds.
In most ball pythons, the black back pattern is just as random as the number and shapes of the alien heads on their bodies. Unless your particular black back came from a known, proven genetic line...the only way to know for sure it is genetic is to breed it out over multiple generations.
For instance.... Here is my black-backed lesser, Spencer:
http://i183.photobucket.com/albums/x...e-oct09-02.jpg
He's from a big name breeder with a great reputation. The breeder says that neither of his parents showed any black back traits at all. So as amazing as Spencer looks, and as hopeful as I am that he has some special genes to pass on...I will not consider his black back traits genetic until I breed him and he passes the trait on to many babies and grand babies.