HISTORICAL MATERIALS/TECHNIQUES

UNDERDRAWING

What is an Underdrawing?
Detecting Underdrawings
Types of Underdrawings
Application Methods
Related Links and Resources
References

What is an Underdrawing?

Underdrawings are preliminary designs that help artists envision and develop their final compositions. Immediately preceding the painting stages, these sketches are applied directly onto the canvas or panel support. Underdrawings can range from very complex to rudimentary simple forms that serve as outlines. Often these preliminary sketches cannot be seen by the naked eye but can be detected with specialized imaging equipment (e.g. infrared reflectography). In certain circumstances, thinly applied paint can become increasingly transparent over time, eventually revealing traces of an artist’s underlying sketch. Underdrawings can help reveal an artist’s working process, distinguish copies from originals, and in some cases offer insight into attribution.

Occasionally artists would apply an imprimatura (Italian) or primuersel (Northern European) either before or after the underdrawing was applied. This layer could either be transparent or colored and would serve either to cut the absorbency of the ground, to impart a slight colored tone to the harsh white color of the ground, or to effectively seal the underdrawing before the painting process was begun.

Detecting Underdrawings

As early as the 1930s, infrared reflectography was developed for use as an examination technique. With this technique it became possible to see through the visible paint layer(s) and reveal preliminary sketches. Infrared imaging is now a routine part of examination, especially with Netherlandish paintings, which frequently feature extensive preparatory drawings.

Types of Underdrawings

Underdrawings can be sorted into two categories, wet or dry, referring to the medium used. Using both infrared reflectography and visual examination, it is sometimes possible to identify distinct characteristics in the line type to differentiate between wet and dry media.

Wet Media

Wet media include diluted paints and inks, or any sort of fluid medium that consists of a coloring agent suspended in a liquid. According to David Bomford, “wet-brushed lines tend to be smooth and continuous and often appear to have puddled slightly at the point where the brush left the surface. Pen drawings can show a line loaded towards the edges by the divided nib.” Dry brush technique, which is delivered in a wet medium, can be easily mistaken for a dry material. The partially dry brush tends to create broken lines that appear similar to marks created by chalk or charcoal on paper.

Dry Media

Dry media include charcoal, chalks, graphite, and metal-point. These materials can leave behind lines that have a steady and consistent thickness; broken or incomplete lines are also indications of dry media. In general, dry media underdrawings can be more difficult to detect than those created with wet media. However, it is not impossible that dry materials were brushed away after lines had been reinforced with a more permanent wet medium, either with ink or with actual paint. It was also not unusual for both a dry and a wet medium to be used within the same composition.

Application Methods

While many underdrawings were completed free hand, there were also several methods used to transfer images onto their intended supports. One such method was tracing. First, the back of a paper support would be colored with black chalk, charcoal, or some type of dark-colored dry medium. Then the drawing would be laid (colored-side down) onto the prepared canvas/panel. A design could be created directly on the paper or reinforced using a sharp tool or drawing implement. Wherever pressure was applied, the black chalk or charcoal would become fixed into place on the support thereby transferring the design. Once the design was transferred it was common for the lines to be reinforced with a more permanent, wet medium.

Another method of transfer was pouncing. This technique was popular in Italy and was also used for wall paintings. Using a metal stylus, small holes were pierced along the contours of a composition that had been prepared on paper. Then, the pierced paper “cartoon” was placed face up on the prepared canvas or panel. Charcoal or black chalk was “pounced” on the surface of the paper, pushing the dry media through the holes onto the support via a pounce bag (a fabric pouch containing dry media). The result left behind a series of dots or “pounce marks” that would next be connected and reinforced, ultimately reproducing the original composition.

Squaring was another method of accurately transferring a preparatory drawing to a substrate. First, a preliminary drawing was executed in the same proportion, but no the same size as the final composition. The artist then drew a grid over the drawing and another grid over the painting substrate in the same proportion but on a larger scale as that of the preliminary drawing.

References

Bomford, David, ed. Underdrawings in Renaissance Paintings. London: National Gallery Publications, 2002.

Cennini, Cennino. The Craftsman’s Handbook “Il Libro dell’ Arte. Translated by Daniel V. Thompson. 1933. Reprint. New York: Dover Publications, 1960.

Walmsley, Elizabeth, Catherine Metzger, John Delaney, and Colin Fletcher, “Improved Visualization of Underdrawings with Solid-State Detectors Operating in the Infrared” in Studies in Conservation, 39 (1994): 217-231.

Walmsley, Elizabeth, Colin Fletcher, and John Delaney, “Evaluation of System Performance of Near-Infrared Imaging Devices” in Studies in Conservation, 37 (1992): 120-131.