Hey- Don't know if Black counts as color henna, but I used the Black this weekend. I did a strand test before I used it and all went well. I mixed the black with henna in a 50/50 mix, I'm really happy w/ the results. IMO Light Mountain is a good strore brand henna. The only thing I could say bad about Light Mountain is that I found their indigo to be a bit gritty, compared to the henna (Reshma) that was so silky it was like baby powder. Don't know if all indigo is grirtty 'cause that was the 1st time I had ever hennaed. The light mountain colors are just mixed by the company to achieve whatever the color. It's almost like they are trying to to take the guess work out of it for the consumer. I also called their customer service dept. They use only henna and or indigo or a combination thereof, they DO NOT ADD anything to it. Do your strand test with some harvested hair form a brush or comb. You'll be fine!
ETA: Since I have now fallen in love with henna and I don't brush. I have been saving and shed hair in a sandwich baggie just to use for future strand tests. HTH.