What's a Finish?
This is a term used in Theatrical Advertising to indicate that the composition "Comp" you were designing or working on was picked as the final, and thus Finished, or will be printed.
I have attached a large JPG showing the posters I have been a part of the finish on. Why a part? Well as a 3D Illustrator I never do the whole poster myself, but work directly with a team of Creative Directors, Art Directors, and Designers to create the final poster. Sometimes it is just the logo like on Superman Returns, or everything except the talent, like the Night at the Museum comp where the Museum Hallway and everything in it is 3D except the talent.
P.S. The Post title links to the best site for seeing Movie Posters the "Internet Movie Poster Awards" or IMPAwards.
You can look up any finish and get an enlargement on this site.