I believe you have to be a donor, though I’m not sure. I’ve seen chatmods do it, and I think you can do it in a anvil with a rank, though. I’ll check the rank store for you. I believe I've seen non ranks do it before, so it must be possible.
UPDATE/EDIT: So I checked all the ranks and none mention coloring. I believe it used to say that, but I don’t know what happened, sorry. You can pm a mod though incase I’m wrong.
It's something that I don't know how to do. I've been trying to figure it out myself tbh. Also! I don't think you actually need a rank to do it, I have a friend, I decline to share her username but she is a non donor and knows how to make the colored items. I haven't got around to asking her how but I'm going to ask her the next time I can.