I am trying to figure out which formula guide to get for a job. It will be on matte paper. Should I get the coated or uncoated book.
I think you kind of answered your own question....
" . . . guide for matte coated paper . . ."
Some print providers (and paper vendors) refer to uncoated stock as "matte".
Other providers/vendors refer to dull coat stock as "matte".
For dull coat, it's still a coat, so coated.
For uncoated, ermm, yeah uncoated :)
The coated/uncoated has more to do with how the stock will absorb the ink. Uncoated stock absorbs more ink. So, colors fade a bit. Dull coated stock is still coated stock, it is just not a glossy coating. So, the ink doesn't absorb as much and using the "coated" formula guide will be closer to end results.
I'd just encourage you to specifiy "dull coat" rather than "matte" since matte can be ambiguous. And everyone knows what you mean when you state "dull coat". But really, that's just a small pet peeve of mine - how the providers/vendors use the same term differently.