Since coloring is a specialized line of work, and practically nobody knows you exist outside of your industry, sometimes there’s sort of a language barrier between you and your director/client.
There’s nothing more frustrating, in any kind of work, than miscommunications and misunderstandings. I’d rather have a picky client rather than one who doesn’t know what s/he wants. It’s still our job, as professionals, of course, to translate what they want into our work. But, it helps if they have at least a little knowledge of our “language” and what exactly we are capable of doing. I once had a client who requested me to put in some text, I think he confused me with the editor…
I am very thankful for Alexis Van Hurkman, a writer/director/colorist based in Manhattan, who wrote an article discussing just that, How to talk to a Colorist. He also has a number of useful and friendly articles, which speaks to both colorists and clients, so, I suggest you poke around his site.
He also recently released a book, “Color Correction Handbook”, which I am very interested in getting, and looks very promising! Color grading books are quite rare and hard to find.