Quick answer on Carol Andress' info...
I can imagine that a small volume copy-shop type printer might be able to get
away with blending inks himself using a kitchen mixer, but for most printers,
who are fanatic on their quality issues, this wouldn't be an acceptable
method. Inks are usually milled extremely finely to assure a smooth even
texture as well as complete blending of the components. While it looks
pretty simple, printing ink is a fairly complex compound with numerous
ingredients combined in very precise amounts.
George Frantz MA/OTA