There is something deeply appropriate about "Appreciations: Karl Knaths," the painting exhibition that goes on view today at the Phillips Collection. Knaths, who died at 80 in 1971, was linked by ties of deep mutual affection to that wonderful museum and its founder Duncan Phillips. "Geraniums in Night Window" (1922), the first painting that the artist sold, was bought by Duncan Phillips. So were many more thereafter, 39 in all. Knaths once told his friend, the poet Jonathan Williams, that there was a period in his life when he "didn't sell a painting for 23 years, except for the annual, crucial behest from Duncan Phillips."

Knaths, like Phillips, loved paintings that were full of complicated color, that acknowledged the French moderns, that were small instead of huge, and that flirted with abstracion but never quite succumbed. From 1938 to 1950, Knaths, who lived in Provincetown, Mass., would come to Washington each winter to teach painting at the Phillips Gallery Art School. Phillips once described Knaths as "a simple man, a man of profound goodness and integrity." Most everyone who knew Karl Knaths speaks with similar admiration of his kindness and his honesty, his teaching and his talk.

The Phillips' little show would fill the viewer with warm feelings were Knaths' pictures better than they are.

They put my teeth on edge. Their colors are too often unpleasantly discordant (Knaths liked to place bright orange next to bilious green). Their mood is cramped and clotted. Their drawing, almost always done in angular black outlines, suggests the worst pretentions of the Frenchman Bernard Buffet.

Once upon a time, these paintings might have seemed to deal rather daringly with the issues raised by European modernism, with Cubism particularly. Now they just seem compromised. Knaths liked a part of Cubism -- its jaggedness, its broken space, its look of tough modernity -- and used his borrowings to forge a style he adhered to most of his long life.

He found his subjects, for the most part, in the humble things he saw around his Cape Cod home, fisherfolk and fishing boats, trees and flowers, deer and dunes, but he always forced these images from nature through his pseudo-Cubist screen. The brushstrokes of his drawing often feel like ax cuts. He liked harsh linearities, and right or acute angles. The flower pot of "Geranium" (1924) has a prow sharp as a knife. The fisherman in "Kit and Kin" (1947) has a black X for a face; in place of nose and eyes, the wife who stands beside him has a strong black T. The hands of the table clock in "Connecticut Clock," a still life from 1947, describe a 90-degree angle: They are set at 3.

Knaths was born in Wisconsin in 1891. He studied at the Art Institute of Chicago from 1912 to 1917, and while there he was much impressed by the famous Armory Show, which after leaving New York went to that museum. In 1919, he moved to Provincetown, where he took a drafty studio -- for $75 a year -- that had been used before by the playwright Eugene O'Neill and the painter Charles Demuth. He kept a home in Provincetown, where many other artists worked, for the rest of his life.

Knaths believed in systems. He had a system for his drawing, and another for his colors. Paul Moscanyi writes that "Knaths chose his color intervals from the Oswald color chart" and his proportions "from a chart, the sections of which represented musical intervals . . ." That may partially explain the harshness that weighs on his art.

Prof. Ben Summerford of American University, who studied with Knaths at the Phillips, writes in the catalogue, "In all my experience with teachers, painters and critics, those Monday mornings with Knaths were the most compelling entry into the world of painting and its meaning I have encountered," and Summerford, himself, is no mean teacher. Painter Jack Tworkov has written that Knaths, up to the mid-1940s, "was truly the most advanced painter in the country." Even Kenneth Clark admires Karl Knaths' art, or did in 1958. Though other respectable judges have spoken warmly of Knaths' art, the exhibit at the Phillips undercuts their praise. It closes Nov. 14.