Magic has no color, sorry but it's the truth. The only real sediment is the intent of your workings.
Please look at basics, your just a magician. Your options come in varieties, if you do a spell for bad luck, it doesn't mean your doing black magic, it means your intent is dark. Just like if you do a health spell, it will show your intention as good. Via like black and dark magic. This isn't however related, so realize it!
I think a little diffrent than most. Where is some day magic had no color that is true. A color is a color. But in this case it's used as a medefore. Black magic is usually dark magic or bad magic. Magic that can do harm.White magic is usually light magic or good magic. Magic that does no harm. Gray magic is an in between stage. One who does both and has trouble deciding which path to take. But onceyou do decide it's hard to go back to the other side. So choose carefully.
Grey to me signifies a little bit of everything. As you mix two colors that were from all the light and all the dark, though regardless it's whatever your intentions are that matter. If you want to use colors as a personal categorization of what you feel is appropriate to place it in that sounds alright to me.
For instance blue magic can signify protection, calmness, and insight so I could associate meditation, protection spells, shielding, and healing.with that colr.
Black magick many see as negativity, absence of, incompleted tasks, or blockade. I could associate the color black with curses, chakra blockage, self work, worry, and different unpleasant emotions.
Though even with your own system of things magic it comes down to your intent and will. Magic itself is simply using energy of the universe to help acquire what you desire. At least it is to me.