Swell guys do not necessarily make swell subjects for films. Just because Marc Chagall is One Heckuva Fella and a Great Artist to boot, is it a good idea to plaster him all over an hour-and-a-half documentary? In the case of "Homage to Chagall," opening today at the MacArthur, the answer, unfortunately, is no.

The difficulty is that producer-director-writer Harry Rasky, a veteran of the TV wars loves Chagall way past the point of distraction. There is so much adulation here, so much homage that the man himself is just about suffocated by veneration, embalmed in the sticky goo of praise.

The form of the film is the conventional documentary one: interviews with the great man interspersed with enough moving camera looks at his art to give the viewer motion sickness. In this particular case, James Mason's cultured voice as narrator and the almost nonstop chamber music background make the film's earnest striving toward "higher things" painfully clear.

Chagall himselff comes across as a charming fellow, justt the kind of lovable old duffer you'd expect from his work. Other things, however, are not so nice.

For this is the kind of film that can't cram in enough sunsets, that considers shots of birds in flight to be inexpressibly poetic. It doesn't even recognize when its being unintentionally funny, as when a real live thunderclap is used to announce the Russian Revolution and in scenes of Chagall's wife's benign ineptitude as an interpreter.

More of a problem are the words themselves. If the voice-overs weren't enough trouble, larded as they are with such portentous bits of over-writing as "the colors of innocence are transfixed by the darkness of anxiety," Chagall's own thoughts are ruined by being recited by actor Joseph Wiseman, who hams it up with an overly theatrical, high-pitched voice that sounds plain silly.

If you love Chagall mindlessly, probably none of this will matter. For everyone else the main question is: How much can I take? The film's undoing is that it was undertaken exclusively as a cinematic good deed, that it has nothing more incisive than pollyannish adoration in mind. Chagall can do very well without all that, and so, for that matter, can everyone else.