John Sergeant, Pencils and Charcoal, 2002, charcoal, black and coloured chalk, white heightening, Private Collection.

The use of charcoal to draw dates back to prehistoric times. During the Renaissance, it was mostly used for preparatory drawings, and it was only in the late 15th century that a method was developed to fix drawings by dipping them in baths of gum . Albrecht Dürer was one of the first artists to use it for portrait drawings. In the early 20th century, artists such as Matisse and Picasso began to use charcoal as a medium for finished works.

This is a softer, reversed version of an image transferred by pressing it to another, dampened sheet of paper. Providing the basic outlines and modelling of the original drawing, it can be worked up into a reverse replica of the original relatively quickly.

In crayons, used by artists such as Watteau, the dry pigment is mixed with wax. It is similar to pastel but greasier and cannot be easily rubbed. It is sometimes difficult to tell the difference on a sheet between between crayon and chalk.

From the Italian word for drawing or design, disegno refers to both the ability to make the drawing and the intellectual capacity to invent the design.

Pouncing involves first pricking tiny holes into a tracing of an image; then, laying this tracing over the desired support and using a small muslin bag with powdered charcoal in it to pat it over the holes, leaving behind small dots on the new surface; and finally, joining up the dots to reproduce the original image.

According to Cennino Cennini, the artist first covered a wall with a rough layer of lime plaster. When it dried, he made his first sketch in charcoal, blocking in the figures and scenes. Then he brushed off the plaster, and using a small, pointed brush and ochre pigments "as thin as water" and without tempera, he painted in the figures in light shades. Then he used the reddish-brown pigment called sinopia, also without tempera, to mark out the noses, the eyes, the hair, and the accents and outlines of all the figures in their correct proportions. When this underdrawing was finished, the artist then applied a new thin layer of wet plaster, covering just enough area as he could work in one day. Before the plaster could dry, he filled in the colours, following the visible lines of the sinopie.

the illusion of the three-dimensions created by means of light and shadow on the flat surface of the sheet or panel.

The squaring on this paper enabled Guercino to transfer his design square by square onto the ceiling. Squaring was one of a number of techniques used by artists since the 15th century to transfer images onto various supports as well as to make workshop copies of master designs.