at least with capes. If you cycle thru the chroma purples on a cape you get purple, silver... and siver again, not black as it should be as the colors in the chromas swape places.
It is more likely that the cape you are applying the material to doesn't have the RGB channel to apply the black material to. Which style are you working with?
Actually I was applying this yesterday as well to the Abyssal Horns and they were always going purple no matter which chromatic material I was using. I know the Abyssal horns by default have an effect on them but I would have expected the chromatic materials to make them either black, purple chrome or chrome, the same way all the other materials make it one solid colour, or is that not how the chromatic materials work? I just assumed whichever was the primary colour would show through, but it seemed not.
I'm going to paraphrase. Basically chromas need RGB channels to work and unfortunately Abyssal Horns don't have the RGB channels in the same way that most of our gear has, so the material gets confused and defaults to something else. I am assuming this is what is happening to the above mentioned cape.
I tried on both the classic cape style, and more to my use the Nabu's Chosen style. I got the same results on both so assumed it was a bug.
Some of these chromas have the same color in the secondary slot. The primary color will always change depending on which version of the material you have, but secondary/tertiary are determined by how they look when applied on our end. I know this doesn't allow for complete customization options! But there are only so many combos we could release per set. Some of the capes are set to just have the secondary color showing instead of the primary.
Because certain materials don't look as nice when they're tintable; the properties that make materials look like what they're supposed to get lost they are a variable.