We custom mix our inks for each job. Our presses are really efficient and we use less than a tablespoon of ink for a set of note cards. A little goes a long way as the inks are like a thick paste. When mixing, we start with some base colors that we combine, often with the addition of black or white to tone down the saturation.
We frequently get requests for tinted embossing. We add a drop of gray ink when we print embossings to give the imagery a bit more of a shadow. The result is subtle, and beautiful when paired with a deeper color.