REFERENCES

Conservator, Worcester Art Museum, 55 Salisbury Street, Worcester, MA 01608.

CenninoCennini, The Craftsman's Handbook, Daniel V.ThompsonJr.ed. and trans., New York, Dover Publications, 1954, p. 91. The chapter number is found in the edition of Carlo and Gaetano Milanesi (II Libro dell'arte o trattato della pittura, di Cennino Cennini da Colle Valdelsa; di nuovo pubblicato con molte correzioni e coll' aggiunta di piu capitoli tratti dai codici fiorentini, Florence, 1859) which was based on an earlier translation of Giuseppe Tambroni (Di Cennino Cennini tratto della pittura, messo in luce la prima volta con annotazioni, Rome, 1821).

The linearity characteristic of some artist's work, Lorenzo Monaco for example, was achieved by a sharper contrast between highlight and shadow. Lorenzo nearly always used a pure white highlight, whereas Pietro Lorenzetti, who was influenced by the more sculptural techniques of modelling prevalent in Florentine painting, allowed a more gradual transition between shadow and highlight. His highlights were usually a pale blue (Pope's HLt: See Arthur Pope, The Language of Drawing and Painting, Cambridge, 1949, pp. 7–8). By modifying the value transition in this way, he obtained the fuzzy quality of modelling that is found throughout his entire artistic output.

Giotto's Maesta in the Uffizi is a good example as is Pietro Lorenzetti's Madonna and Child with Eight Angels, dated 1340, also in the same Gallery.

There is a sharper division between the highlights and middle tones than one can perceive on paintings definately attributable to the master. A particularly striking comparison may be made between the Virgin Annunciate in Lorenzo's signed Coronation of the Virgin in the Uffizi, and the Simon painting. The Uffizi polyptych is dated 1414 and the Simon Virgin Annunciate was once a pinnacle over the Coronation in the National Gallery, London, which has been dated shortly after the Uffizi painting. For a discussion of these two works, see Martin Davies, The Earlier Italian Schools, London, The National Gallery, 1961, pp. 306–309; and Georg Pudelko, “The Stylistic Development of Lorenzo Monaco—I,” The Burlington Magazine, 73, 1938, pp. 237–248. The Simon panel is illustrated and described on p. 247.

Interesting examples are Baldovinetti's Annunciation, Florence, Uffizi, and Master of the Crivellesque Polyptychs, Polyptych: Madonna Adoring the Child in her Lap; SS. Bonaventura, Michael, Francis and Bernardino of Siena, Formerly Harewood House, Earl of Harewood. Baldovinetti's painting is dated shortly before 1460 and the Crivellesque Polyptychs Master's to the late 15th century. Both paintings are illustrated in Berenson's Italian Pictures of the Renaissance; the former in Vol. II of the Florentine School, London, 1963, Pl. 795; and the latter in Vol. II of the Central Italian and North Italian Schools, New York, 1968, Pl. 965.

A discussion of Byzantine fresco incisions may be found in D. C. Winfield's “Middle and Later Byzantine Wall Painting Methods. A Comparative Study,” Dumbarton Oaks Papers, 22, 1968, pp. 61–139. Many artists worked in both fresco and panel painting, and ideas that were developed in fresco were frequently transmitted to panel painting. An example of this is Simone Martini's punchwork decoration that appears in his frescoed Maesta of 1315 and was adopted by him for his Naples panel of 1317.

Neither azurite nor ultramarine blue is strongly opaque to X-rays. For a discussion of their properties, see JoycePlesters, “Ultramarine Blue, Natural and Artificial,” Studies in Conservation, 11, 1966, p. 72; and R. J.Gettens and E. W.Fitzhugh, “Azurite and Blue Verditer,” Studies in Conservation, 11, 1966, p. 57.

While Tintori and Meiss (The Painting of the Life of St. Francis in Assisi, Norton Paperback N393, 1967, p. 62 and 171) frequently make references to the grey or red washes underlying the azurite blues in the Assisi frescoes, no explanation was given for them.

The X-radiograph was exposed for 90 secs, at 5 MA and 40 KV. A sample of paint was extracted from one of the incised lines, mounted in casting resin and ground down to cross-section. A thin layer of grey paint (white and black particles) had been brushed directly over the gesso, and some of it collected in the incised lines. See my “Observations on the Painting Technique of Luca di Tomm�,” Los Angeles County Museum of Art Bulletin, 19, 1973, pp. 12–21.

I have observed instances in which the artist executed the mantle in a two-value system without the aid of incised lines.

The probable use of drawings in Early Italian Painting was discussed in the article by Ben B.Johnson and Norman E.Muller, “A Study of Technical Aspects and Stylistic Sources of The Martyrdom of Pope Caius by Lorenzo Monaco,” Archivero I, Santa Barbara, California, 1973, pp. 23–56.

CenninoCennini, op. cit., Chapter LXXXIII, p. 55.

This painting is in exceptionally fine condition. A diagonal scrape mark is found through the robe of St. John and the surface is covered with a thin, uneven yellowish film. The ultramarine blue mantle of God the Father preserves the blue black shadows that Cennino recommended (see n. 12 above), but no incised lines have been observed in it.

The Crucifixion, like the Trinity, is in superb condition for a painting of its age. The gold leaf is clean with no evidence of wear. Unfortunately, the figures seem to be covered with a grey layer (darkened egg white?) that makes them difficult to read. A cleaning was attempted in the past but was abandoned as being too risky. Still, the clarity and crispness of the surface detail is there for all to study.

Azurite blue, when mixed with the yoke of egg, tends to turn slightly green. Because of this, it was not as frequently modelled in the same way as ultramarine, which was discussed in the first section of this article.

Ultramarine blue appears red on a color infrared transparency owing to the sensitizing of the cyan or infrared sensitive layer in the emulsion. Azurite appears blue or blue black. For a more detailed discussion of this film's properties, see CharlesOlin and ThomasCarter's “Infrared Color Photography of Painting Materials,” in: Papers of the American Institute for Conservation (A. I. C.), Los Angeles, 1971, pp. 83–87.

The final arbiter in this case should of course be optical or chemical analysis of the mineral grains. In view of the raised quality of the ultramarine blue, this paint should also be tested for the type of medium present.

A full discussion of this painting is found in Luisa Marcucci's I Dipinti Toscani del Secolo XIV, Rome, 1965, pp. 168–169.

ErlingSkaug, “Notes on the Chronology of Ambrogio Lorenzetti and a New Painting from His Shop,” Mitteilungen des Kunsthistorischen Institutes in Florenz, 20, 1976, p. 314 and n. 43. Pietro's punch mark is no. 29 in Table II, p. 330.

Cennino, op. cit., Chapter CXL, pp. 85–86.

Sgraffito was a method of depicting gold embroidered drapery by completely covering gold leaf with egg tempera paint and then scraping away patterns of the paint down to the gold leaf. See. Cennino, op. cit., pp. 86–88.