To mark the 500th anniversary of the life of Leonardo da Vinci, the Royal Collection Trust under the auspices of Queen Elizabeth II has published a lavish edition of the drawings of Leonardo, one that investigates the various materials and methods employed in the extraordinary collection of Leonardo drawings housed in the Print Room at Windsor Castle. Revealed through an array of scientific technologies that include visible infrared transmittography, ultraviolet and multispectral imaging, optical microscopy, X-ray fluorescence, Raman spectroscopy and synchrotron-generated XRF microanalysis, drawings were scrupulously examined to expose paper composition, ink compounds and hidden media, implement imprintation, preliminary sketches, erased marks, inscriptions, watermarks, luminescence and other features of artworks obscured for over 500 years.

Authored by Alan Donnithorne, Conservator of Prints and Drawings at the British Museum and Chief Restorer of Drawings at the Royal Library, the study was undertaken by one uniquely positioned to examine the renowned collection of nearly 600 drawings held at Windsor Castle. Based in part on prior research projects carried out with the British Museum’s Department of Scientific Research, this text offers the first in-depth study focused exclusively on Leonardo’s drawing materials and working methods “seen through a microscope.” As a complement to esteemed studies by Kenneth Clark originating in 1935, followed by Carlo Pedretti’s focused catalogues of Leonardo’s nature studies, anatomical drawings and horses in the Royal Library, Donnithorne’s investigation provides invaluable primary evidence for Leonardo scholarship in areas of conservation, art history, fine art and collection. It also expands significantly upon the acclaimed Leonardo da Vinci, Master Draftsman catalogue issued to accompany an exhibition at the Metropolitan Museum of New York in 2003 through penetrating scientific scrutiny that points up the import to meaning of every facet of Leonardo’s artistic process.

Sections of the text provide in-depth examinations of the lines and brushstrokes, papers, styli, metal points, inks, chalks/charcoal and brushes used in the production of the drawings. Analytics common to conservators reveal the artist’s manner of working, the pressure and direction of his hand, differences of touch and the way the drawing tool was moved across the paper. These factors serve to identify such features as the sharpness of outlines, the softness of blended shadows, the thin transparency of washes and accretions of ink. Placing primary emphasis on disegno, the act of drawing as the artist’s means towards the realization of ideas, the author inspects the many kinds of marks described by Leonardo as outlines and lines that curve to one side or another, broad or fine, blended without strokes in parts to achieve the highest degree of brightness and shadow.

In the papers chosen by the artist, Donnithorne emphasizes the importance of support in the appearance of the drawings, the character of the marks left on the surface intimately dependent on the paper’s integral composition and the way the artist’s drawing tools interact with it. He considers a variety of papers favored by Leonardo from the finest white to the coarsest brown along with subjects and treatments the artist reserves for each. This chapter includes an account of the origins of papermaking in the west from its foundations in thirteenth century Italy and a detailed description of artisanal papermaking in the early Renaissance. Among Leonardo’s studies he notes qualities of color, brilliance, texture and luster impacted by the paper together with fabrication details such as fibers, laid lines, deckle and watermarks made evident through transmitted light. An especially evocative drawing of an old man with flowing beard, for example, one of the last by Leonardo, is full of fibers that include straw and rope, knots and shive, accented by an imperfection in the paper, a lump above the eye in the drawing’s upper center.

Chapters on stylus and metal point examine drawing instruments in brass, the lead and silver styli referred to as silverpoint, and the grounds of powdered bone applied as coatings for metal point. Elemental maps and specular reflections show the relative distribution of silver in a metal point study of a horse on blue-grey prepared paper; logarithmic scale graphs indicate their silver, copper and mercury content; and brilliantly colored magnifications display the heightened contour of a horses’ legs. In a design for an equestrian monument, Donnithorne writes that the “lines of thin-drawing positively gleam with metallic intensity when viewed at an angle against the light.” (86)

The eloquent correspondence between particular subjects, their virtuosity of rendering and the materials and methods employed in their facture rises at times to a level of poetry. Within a sheet filled with diagrams and notations for various mechanical apparatuses, an infrared transmission discerns the watermark of a mermaid with perfect clarity. Other watermarks, unveiled beneath the head of a youth in profile and studies of the heart, include the hind legs of a prancing dragon, a Catherine’s wheel and an eagle in a circle. These emblematic drawings seem to emerge from the very core of the support, soul-like, drawn in light. Exposed through ultraviolet-induced imaging, glints of white heightening over red chalk on pale red paper take on the appearance of ethereal luminosity in The Alps seen from Milan. Carbon black imbues the drapery of a kneeling figure with tender poignancy; wetted chalk suffuses the head of Saint Anne with a delicate sfumato halo. There are punch marks used for charcoal-dust transfer and blind stylus diagrams of polyhedrons, cubes, circles and arcs--geometric tracery made with instruments such as compasses tipped in steel.

This publication’s quintessential beauty extends beyond the elegance of Leonardo’s drawings to the incomplete, often fragmentary images captured through state-of-the-art technology—the haunting, partially erased underdrawing of a human skull, the faded metal point of neck and hands, the black chalk muscles of a human leg. Artfully interwoven are the works of the artist with other Renaissance paintings, manuscripts and frescos; passages from such sources as Cennino Cennini’s Il Libro del Arte and Giorgio Vasari’s Lives of the Artists; exacting diagrams and graphs; and photographs that include spectacular full-color microscopic and macroscopic details. Not confined to medium or epoch, Donnithorne’s text integrates multiple perspectives, contexts, cultures and chronological periods in authoritative historical exposition. It is especially commendable in its seamless integration of science, art and technology together with an approach that fuses logistical analysis with art historical interpretation. Emblematic of the embryonic/gestational nature of Leonardo’s inspiration, and pointing to the promise of future research, Donnithorne’s study opens and closes with one of the artist’s best-known drawings – a fetus in the womb of 1511, executed in pen and ink, red chalk over black chalk, with notes on reproduction and sketches of the fetus in the womb on the verso. It alludes obliquely to Leonardo’s spirit of inquiry to which, in the words of Sir Kenneth Clark, “the vast corpus of modern scientific knowledge owes its origin,” and to Leonardo’s own conception of disegno, inscribed in the drawings as his advice to painters to apply themselves first through draughstmanship “to giving a visual embodiment to your intention and the invention which took form first in your imagination.”