Mistress Among the Masters : MATISSE AND PICASSO; A Friendship in Art <i> By Francoise Gilot (Doubleday: $30; 304 pp.) </i>

Henri Matisse, that magician of brilliant interiors from which any kind of muted tone, let alone shadow, had been banished, presented a puzzling aspect to the young painter Francoise Gilot when Picasso first took her to visit him in the south of France just after World War II. He lived, it seemed, largely in darkness: “All shutters were closed; everything stood still in obscurity.” As her eyes became accustomed to the penumbral light, objects began to emerge: a blue china pot with polka dots, a pineapple on a garden seat, birds in a cage.

They all were familiar to her since she, about to become mistress of a genius--and who would become renowned for her unsparing portrait of their relationship in “Life With Picasso”--was, it seemed, even more in awe of Matisse than she was of her lover. As a young art student painting in oils, she found herself obsessed by this powerful sensualist, master of color, of harmonies and dissonances, and the effects to be achieved on the viewer’s imagination by the right painterly juxtapositions. She too wished to evoke emotion with the same directness, exuberance and magical sleight of hand.

For, as she makes clear, artists of her generation were still completely dominated by the giants who had preceded them and the roles they believed themselves destined to play. She was not among those who, convinced of the necessity for a New Order, would recoil in horror from any knowledge of historical precedent, lest contamination should follow. Rather, she and her friends earnestly debated the influence, merits and effects of the masters, measuring themselves more or less consciously against them since, as she wrote, “art arises from art as much as from nature.”

Such musings were occasioned by her decision to describe a friendship in the years immediately following World War II and the meetings she witnessed between Picasso (by whom she would have two children before leaving him) and the senior Matisse, the one artist, Picasso would declare, whose work meant anything to him.

Their encounters took place in the South of France, but also in Paris where, just after the war, the atmosphere of the 19th Century still lingered and it was possible, if one were an artist, to live a life of almost dreamlike enchantment--at least before the Rive Gauche became fashionable.

It is the faded but still poignant allure of those days in the late 1940s and early 1950s that, like some wonderful old perfume concocted from genuine flowers, pervades this book. For, as Gilot also writes, painters who had reached the stature of Picasso and Matisse were expected to be maitres a penser , theoreticians of consequence.

Being so accomplished could only mean (according to French logic) that they had consciously arrived at carefully evolved sets of principles that explained the power of their art. And so we are given lengthy discussion although, when one reflects that these took place 40 years ago (imagine trying to reconstruct a conversation one had last week, let alone last year), one has to doubt that the weighty statements ascribed to these artists were ever spoken.

However, Gilot doubtless has faithfully reported the atmosphere of the exchange, the fact that each was struggling to describe his work in words; struggled because, despite these heroic attempts at self-analysis, debates about art, abstractions, composition, philosophy and so on seldom amount to much. What is more typical is a failed attempt at profundity, such as an astonishing passage in which Matisse and Picasso humorously debate the former’s assertion that good art ought to ressemble an armchair.

This is, in short, the kind of book any French aesthetician would love, and one is tempted to conclude that Gilot, dissecting and analyzing the strengths and weaknesses of the geniuses she is privileged to know, ascribes qualities to them after the fact, and invents motivations, as if everything could be explained that way. The effort is well meant but it is difficult to retain even a fraction of the arguments. The book’s strength comes much more from Gilot’s remarkable gift for describing appearance and personality, background and mood.

Upon first meeting Matisse, for instance, she found him in bed, sitting erect and playing with a cat. “Despite the fullness of his features, he communicated energy. There was no heaviness, no cumbersome mass, just the opposite--an elan, a sense of weightlessness. We met the youth of his light-blue gaze through his glasses.”

Matisse, she wrote, took an immediate liking to her and wanted to paint her, which annoyed Picasso and brought out all his possessive instincts; indeed, she believed Matisse’s marked interest acted as the spur that made Picasso decide she should become his live-in lover. Then Picasso began to paint a portrait of her in the nude, “ La Femme-Fleur ,” saying as he worked, “Matisse isn’t the only one who can paint you with green hair!”

Much as Picasso loved and admired Matisse, he was always looking for the fatal flaw. One evening at dinner in a restaurant he found a hair in his soup and quipped that it looked like one of Matisse’s line drawings. That joke eventually got back to Matisse, who found his own way of getting even. He presented Picasso with a perfectly ghastly, enormous statue from a remote island in the Pacific and insisted that he accept it.

The undercurrents of attraction-repulsion between the two painters is well described in “A Friendship in Art,” as is the relationship Gilot shared with them both--although, obviously, one would have loved to hear about it all from Picasso’s and Matisse’s point of view.