What substances are typically used to produce cyan, magenta, and yellow ink?

Early in grade-school you learn *blue, red, and yellow* are the primary colors that can be used to produce any other color. If you're curious enough, you later learn the primary colors are actually *cyan, magenta, yellow* and -- for practical purposes -- key (*black*). 


My question is, **what substances are used for each of these pigments and where are they found?** Are they synthesized? 


To be concrete, what substances are inside the in CMYK inks found in desktop inkjet printers?


