Albrecht Dürer, Salvator Mundi ca. 1505. An unfinished painting and IR image clearly show the under-drawing that closely resembles Duerer’s drawings and etchings. The MET Museum

Underdrawing and its function

Materials & Tools

An essential step in the painting production process was the underdrawing. Northern and Southern, Renaissance and Medieval, oil and tempera painters all used under-drawings in their works.

The function of the underdrawing is to develop shapes, proportions, tones and volumes of the design prior to applying the color. Since both tempera and initially oil colors were applied mostly as transparent glazes, the under-drawing would remain visible through the layers of colors.

§ 85. Drawing, by transfer or directly.

[…] Thus it is seen that the artist, after the priming is dry, either tracing the cartoon or drawing with white chalk, makes the first sketch 4 which some call ‘imporre’ (getting it in). And having finished covering the whole the artist returns to it again to complete it with the greatest care: and here he employs all his art and diligence to bring it to perfection. […]

Giorgio Vasari (1511-1574), Vasari on technique; being the introduction to the three arts of design, architecture, sculpture and painting, prefixed to the Lives of the most excellent painters, sculptors, and architects
Jan van Eyck (ca. 137090-1441), Saint Barbara, 15th century oil on panel, 31 x 18 cm Koninklijk Museum voor Schone Kunsten Antwerpen

Cennino Cennini also suggest first make a drawing with charcoal on the panel, then dust it a away and reinforce with ink:

[…] And take a little dish half full of fresh water, and a few drops of ink; and reinforce your whole drawing, with a small pointed minever brush. Then take a little bunch of feathers, and sweep the whole drawing free of charcoal. Then take a wash of this ink, and, with a rather blunt minever brush, shade in some of the folds, and some of the shadow on the face. And you come out with such a handsome drawing, in this way, that you will make everyone fall in love with your productions.

The craftsman’s handbook by Cennini, Cennino, active 15th century; translated by Thompson, Daniel Varney, 1902- ed

Vasari complements Tuscan painters for basing their paintings on design/drawing and criticizes Venetians for having a much less structured manner of work, but in fact Venetian painters, such as Giovanni Bellini to give an example, also based their art on extensive preparatory work of drawings, cartoons and under-drawings.

Compianto su Cristo morto Giovanni Bellini (1459-1516), Oil on panel, 73 x 119 cm, Uffizi Gallery
The purpose of this panel is still lively discussed among art historians, but most agree that it is an unfinished work.

Bellini was known and even criticized for making extremely detailed underdrawings:

“draw the boards with such extreme diligence, composing the whole of light and dark, as Giovanni Bellini used, for it is labor discarded, having to cover the whole with the colors”.

[…] e non uoler […] disegnare le tauole con tanta istrema diligenza, componendo i il tutto di chiaro, et scuro, come usava Giouan Bellino, perch’è fatica gettata hauendosi à coprire tutto con li colori

Paolo Pino, Dialogo di pittura 1548
Adoration of the Magi, Leonardo da Vinci (1452 – 1519), Mixed media on panel, 244 x 240 cm, Uffizi Gallery

In tempera painting process, the underdrawing would be normally executed with ink directly on the gesso ground, then the artist would lay gold leaf or add three-dimensional decorations in pastiglia and would proceed to laying the tempera colors directly on top of the under-drawing.

When painting with oil colors, additional layer/s may be applied under or on top of the underdrawing. This isolation layer is called imprimitura. The underdrawing itself can be as well executed directly with oils.

Check out this interesting study of the Hidden Layers (such as underdrawings, cartoon tracing marks, pentimenti and more) of paintigs that chan be revealed with help of infra-red and x-rays.

Fra Bartolomeo, Pala del Gran Consiglio [DETAIL], Museo nazionale di San Marco di Firenze in this unfinished panel both traced cartoon and underdrawing can be seen.