Florence celebrates a master: Raphael

Florence celebrates the fifth centenary of the birth of Raphael this year with a series of exhibitions giving probably the most complete survey ever offered of the renaissance artist. The main exhibition is a unique opportunity to see the biggest collection of Raphael paintings ever housed under one roof.

Eighteen canvases from the Pitti Palace and Uffizi Gallery collections are displayed in the Sala Bianca (White Hall) of the magnificent renaissance Pitti Palace. In adjoining rooms there are two further exhibitions - a collection of 50 drawings, preparatory sketches for his paintings, and a fascinating display of diagnostic photo research carried out on most of the exhibits. A further exhibition of Raphael's architectural plans for the 16th-century Florentine Pandolfini Palace is housed on the ground floor, while a separate exhibition is set up, fittingly, in Michelangelo's house (Casa Buonarotti), which consists of drawings by both Raphael and Michelangelo illustrating the elder renaissance artist's influence on the younger Raphael.

Despite criticism charging overtly simplistic hanging of the paintings on a dead white background, the exhibitions are drawing an estimated 2,300 visitors a day. The pictures are divided into two sections. Works from Raphael's early years in the northern town of Urbino, his birthplace, and his apprenticeship and study years in Florence, are in one section, and works from his late period, in Rome, where he worked until his death in 1520 at age 37, are in the other.

''You can clearly see the development of a young artist with remarkable psychological insight and that idealized beauty he painted, to the greater freedom and majesty of line and style of his Roman years,'' says Prof. Mina Gregori, responsible for the artistic organization of the exhibition.

One or two of the paintings have the words ''attributed to'' in the catalog, such as the portrait of Elisabetta Gonzaga, although Professor Gregori feels this is beyond doubt the work of the artist she calls ''the initiator of portraitism in the 16th century.'' In most cases of previously doubtful authenticity, such conviction is confirmed by the laboratory research work displayed in the exhibition, directed by diagnostic expert Maurizio Seracini.

Here a display of reflectography studies reveals a whole series of surprises beneath the surface of Raphael's works. The flawless beauty, for instance, of the ''Madonna del Granduca'' (''Grand Duke Madonna''), painted soon after the young artist's arrival in Florence (1505), portrays a madonna holding her child against a sheer black background. The reflectography photogram, however, shows an arched window and a hint of landscape behind the head of the madonna. Similarly, in the group portrait known as the ''Madonna dell'Impannata,'' painted about six years before the artist's death, one of the figures is an adolescent St. John the Baptist. The reflectographic eye shows that this figure was painted over a bearded St. Joseph holding a small child.

Apart from discerning the artist's second thoughts, reflectography, according to Seracini, goes a long way toward confirming authenticity of those works of doubtful origin. The much-discussed authorship of a self-portrait of the young Raphael, said to be painted about 1506, has now been almost 100 percent authenticated by the infrared camera used in the reflectography technique. It shows a charcoal drawing of the details of the hands and facial features beneath the color, clearly in the style of Raphael. In other cases the basic drawing for a painting is shown up as being done with the ''spolvero'' technique of perforating a paper tracing of the outlines of the original drawing and rubbing powder through the holes onto the canvas. This was a method often used by Raphael, who, as the collection of his drawings shows, was a meticulous draftsman.

Seracini's diagnostic laboratory is showing off its widest range of achievements so far. Other important undertakings include diagnosis preparatory to restoration on Leonardo da Vinci's ''Last Supper,'' now being restored in Milan, and Botticelli's now restored ''Primavera'' (''Spring''). On this, Seracini collaborated with the respected American restorer Travis Newton in 1975 and '76.

''What we have done here,'' remarks Seracini ''not only throws new light on Raphael's technique but also shows the true state of conservation of the works.'' In fact, the collection is for the most part restored to near-pristine brilliance, and includes such masterpieces as the ''Madonna della Seggiola'' (''Madonna of the Chair''), which Nathaniel Hawthorne noted in his diary as ''. . . The most beautiful picture in the world.'' There are also the portraits of Raphael's patrons Pope Leo X and Pope Julius II - the latter described by Giorgio Vasari, a 16th-century biographer of renaissance artists, as ''so wonderfully lifelike and true that it inspired fear as if it were alive.'' And the ''Madonna del Cardellino'' (''Madonna of the Goldfinch''), in which St. John the Baptist offers a tiny bird to the madonna. Vasari comments that the subjects in this painting are ''well colored and carefully finished, so that they appear to be actual living flesh.''