From how I know it, like Ralph says, the only true genetic black backs are het reds. I always assume anything else is just a nice description of the animal.

On that note, not all het reds have those nice black backs with no dorsal pattern.

That animal above reminds me of my female that has a dominant black back like feature.

It's a little difficult to see in this picture...
Here
but she does have a nice dorsal stripe. I consider her to have a nice black back. It's nothing like a het red... but still a very dominant feature.