copyright trademark infringement, under CO law is it okay to take image of actor and sell it on t-shirts

First, don't take legal advice from teachers who aren't licensed to practice law. There is no "80%" threshhold - or any other percentage - that puts you in the clear.

If the photograph is from the 1980's then someone, most likely the photographer, is the owner of the copyright in the image. Reproducing it on a t-shirt without permission would likely violate copyright. Your teacher may have been confused about the "fair use" doctrine, which allows you to use portions of copyrighted works for purposes of criticism, commentary, and similar uses. The test for whether something is fair use has multiple factors, none of which are conclusive, but one of the most important is that your use of the image on the t-shirt would take away from the photographer's ability to make a profit by doing the same thing (effect on the market test). So this use would likely infringe his copyright, with no fair use defense.

As far as trademark goes, Molly Ringwald - like any other actor- may or may not have a trademark interest in her name and likeness. She would almost certainly have an interest in her "right of publicity" - depending on state laws where you sell the t-shirt - and your use of her name and likeness could expose you to liability that way.

If you want to make money doing something like this, get an experienced lawyer on retainer first.

The prior answer was very good, I just want to emphasize that even if there is no trademark or copyright issue, there could be a state-based issue in connection with Molly Ringwald's right to prevent others from using her face or appearance -- her likeness -- in any commercial venture, that is not dependant on trademark or copyright violations..

Agreed with both of the answers above--just keep in mind and look into Right of Publicity and also consider that you cannot develop trademark rights in the name, portrait, or signature identifying a particular living individual except by that individual’s written consent…

Please note that this information is for informational purposes only and is not legal advice and should not be construed as legal advice. Nothing herein is meant to create an attorney-client relationship.