Drawing materials

Chalk

 

 

Baths of Nero, Rome

Conjectural reconstruction of the Baths of Nero, Rome Enlarge image

Conjectural reconstruction of the Baths of Nero, Rome
III/2r, Andrea Palladio (c.1540)
Copyright: RIBA Library Drawings Collection

Reverse of Baths of Nero, Rome

Conjectural reconstruction of the Baths of Nero, Rome Enlarge image

Verso of Palladio's conjectural reconstruction of the Baths of Nero, Rome
III/2v, Andrea Palladio (c.1540)
Copyright: RIBA Library Drawings Collection

Palladio used red chalk in several of the earlier drawings in the RIBA Drawings Collection primarily as a copying tool or for under drawing. The chalk is made from the rock haematite, or iron oxide, and is suspended in clay. It is also known as sanguine, crayon rouge or matita rosa.

The first documented use of red chalk was in the drawings of Leonardo Da Vinci. It is light, reliable and fairly easy to use, and so became very popular with artists and draughtsmen.

Red chalk varies in tone depending where it has come from, and so Palladio's drawings would differ in colour and depth. Wetting chalk gives it a more intense colour and helps it flow across the paper. Chalk is held together by its clay properties, and this gives it a smooth texture.

In Palladio's day artists would use chalk as a main drawing implement for under drawing or to highlight areas or add contrast. Sometimes it was applied to the back of a sheet as an early form of tracing, as seen in Baths of Nero, III/2. The black chalk, obtained from carbonaceous shale, on the reverse of sheet III/1, Baths of Nero also suggests that it too was used to trace with.

On sheet III/2 heavy lines can be seen on the image side of the sheet where the object has been pressed or possibly folded to copy. The chalk on the reverse of the sheet would have been applied wet to make transference possible. As a result it appears dense and flat.

Natural chalks are easy to use as they require little preparation. They simply need to be shaped into a usable form, although red is much harder than black or white and therefore more difficult to shape.

Natural red chalk is fairly stable when exposed to light. It does, however, remain highly soluble. This poses problems for the conservator as it makes water treatments hazardous.

Chalk degrades as moisture evaporates the clay component. This can make pigment disperse. It can easily smudge or rub against another drawing, leaving its mark upon it.

Drawings made with either graphite or chalk need to be stored carefully in deep mounts using a cover of a silicon coated paper, which prevents the graphite or chalk from transferring and offsetting onto other drawings.