Do you paint?

When I took up painting as a hobby several years ago I had no idea that, besides getting pleasure from it, I would gain exceptional insight into human nature. Now, in addition to being able to fashion from a sugar bowl, a copper kettle, two apples, and a lemon something approximating a still life, or as the French so descriptively call it, ''la nature morte,'' I can deduce with a reasonable degree of accuracy the character of a man or woman from their remarks on seeing a painting - particularly if he or she doesn't like the painting.

There are those, for example, who face the truth and make the best of it, like my brother. I had sketched in his portrait and was beginning to paint the details when he remarked that there wasn't much of a resemblance.

''But that's all right,'' said my model. ''You're starting a new trend. O Pioneer! You're merely reversing the usual process. Why be old fashioned and find your sitter first? Paint the picture and then go out into the highways and byways to look for the subject. Think of the excitement of peering into every face on the subway, rushing to the rail at the airport to see the people coming off the planes, dashing. . . .''

I had to throw my best bristle brush at him.

Others (they are the uplifters) feel that it is their mission to encourage amateur artists, particularly those who have started to paint in middle life. ''How wise you were to take up painting when you stopped playing tennis,'' exclaimed Phyllis. ''Now don't let it disturb you that the others in the art class are only kids. Why, Grandma Moses didn't start to paint until she was in her 70s, and look how far she got. They have made Christmas cards, china, and goodness knows what else from her paintings.''

I thanked Phyllis while I felt for wrinkles creeping into my cheeks and began watching my hands for a tremor.

The clever disguisers are the strictly truthful folk who are nevertheless too delicate to hurt one's feelings and who search for original ways to sidestep the issue by saying obliquely, looking at a still life, ''Portraits are really your forte, you know,'' or, brightly, ''I couldn't do as well, I'm sure.''

Since in our apartment a flower painting hovers near the piano, a still life of vegetables and fruit hangs at one end of the kitchen, and three portraits adorn the bedroom, it is practically impossible for any visitor to fail to notice and comment on the pictures. Escape me never! This gives me unparalleled scope for character analysis. The classifications are ready, the study of human nature goes on apace.

''I like the frame'' - school of frankness unabashed, quite refreshing at times. ''Those are onions, aren't they?'' - irresolute but anxious to show interest. ''You must have a lot of fun doing this'' - evasive, determined to be agreeable at all costs. ''How long have you studied?'' - procrastinator, playing for time to think up the best remark.

Now with one-third of the nation, more or less, out painting from unprotesting nature, poring over still lifes composed of the vegetables and fruits you should have had for dinner tonight, or impressing family and friends to serve as models, it is time to decide what your line will be when that inevitable moment comes in which you will have to comment on an amateur's work. Will it be the truth? Deception? Evasion? Think well, for the would-be artist is probably also a first-class observer of human nature, and you may be giving away more than you realize.

Last week I stood in front of a brilliant Cezanne in one of the big New York galleries, looking carefully at the bold strokes of color, when a young man next to me murmured, ''What a fellow, isn't he? Do you paint?''

I admitted I had taken up painting. ''Not serious, of course,'' I added hastily, ''just as a hobby.''

He looked at me kindly. ''But why not seriously?'' he insisted gallantly. ''Now, Grandma Moses . . . .''