kinda chiming in a little late here as well...
Locally, The best way is get involved in the scene...
go to galleries, meet the gallery owners...
talk to people.
a good balance art crowd is:
and the third half are families and friends of the artists, and/or the "I'm-just-here-for-the-cheese-and-wine" crowd.
the questions to keep in mind for yourself...
- is this gallery showing work similar in genre to mine (don't approach a sculpture gallery if all you do is watercolors.)
- ask other artists (especially artists of similar genre) if they are represented and if so by whom (maybe ask too if they are pleased with the level of service)
- I strongly suggest that you not limit yourself to a local market... you want more people to see your work.
the common path with art representation is
show in galleries, collect a portfolio and parlay that in the door of artists agents.
(we here on this list - none of us are common - but it is nice to have this information)
some times if you are able to have a show in a reputable gallery, you will be offered representation... either by the gallery or the gallery may suggest someone to you.
a website is great to be able to refer people to.
I too, am not familiar with the term "master colorist"... but, if this is someway connected to publishing, then approach a literary agent.
Also... there is a publication (on-line or paper versions) called Art Opportunities Monthly
I have subscribed to the on-line version for a number of years it is well worth the price (it is something like $20 a year) Amazing opportunities in all branches of the arts - writing, film, visual arts... competitions, grants, residencies, publications and just opportunities to show locally and internationally...
This is an American publication, so it is mostly focussed on opportunities available to US citizens.
good luck to your friend....