I will agree with the seller who says the black coloring will make the candy bitter. The school colors in my town are red and black and I have eaten a few black graduation party candies.....all are awful!
You could try to melt black licorice....don't know if it'll work...but that's the only alternative I can think of....or just go with the red....but I can taste any intense food coloring.
Linda C

You need to go buy black powder that you can find in stores that sell cake/candy decorating supplies. Its used to color frosting on cakes. Add that to the dark chocolate until you get the color you are looking for.
I had to make black roses for a school graduation and that is how I did them. It doesn't change the taste of the chocolate.

Use melting wafers like Merckens or Nestles. These come in all different colors and flavors. YOu should be able to get red.

If you take white chocolate and add the black it will come out gray.

Hope this helps.