Pastel is an art medium in the form of a stick, consisting of pure powdered pigment and a binder. The pigments used in pastels are the same as those used to produce all colored art media, including oil paints; the binder is of a neutral hue and low saturation.
Pastel sticks or crayons consist of pure powdered pigment combined with an inert binder. The exact composition and characteristics of an individual pastel stick depends on the type of pastel and the type and amount of binder used. It also varies by individual manufacturer.
Dry pastels have historically used binders such as gum arabic, gum tragacanth. Methyl cellulose was introduced as a binder in the twentieth century. Often a chalk or gypsum component is present. They are available in varying degrees of hardness, the softer varieties being wrapped in paper.
Dry pastel media can be subdivided as follows:
- Soft pastels: This is the most widely used form of pastel. The sticks have a higher portion of pigment and less binder, resulting in brighter colors. The drawing can be readily smudged and blended, but it results in a higher proportion of dust. Drawings made with soft pastels require a fixative to prevent smudging.
- Hard pastels: These have a higher portion of binder and less pigment, producing a sharp drawing material that is useful for fine details. These can be used with other pastels for drawing outlines and adding accents. However the colors are less brilliant than with soft pastels.
- Pastel pencils: These are pencils with a pastel lead. They are useful for adding fine details.
In addition, pastels using a different approach to manufacture have been developed:
- Oil pastels: These have a soft, buttery consistency and intense colors. They are slightly more difficult to blend than soft pastels, but do not require a fixative.
- Water-soluble pastels: These are similar to soft pastels, but contain a water-soluble component, such as glycol. This allows the colors to be thinned out using a water wash.
- A pastel is made by letting the sticks move over an abrasive ground, leaving color on the grain of the paper, sandboard, canvas etc. When fully covered with pastel, the work is called a pastel painting; when not, a pastel sketch or drawing. Pastel paintings, being made with a medium that has the highest pigment concentration of all, reflect light without darkening refraction, allowing for very saturated colors.
Pastel supports need to provide a "tooth" for the pastel to adhere and hold the pigment in place. Supports include:
- laid paper
- abrasive supports (e.g. with a surface of finely ground pumice or marble dust)
Protection of pastel artworks
- Fixatives: Some artists protect their finished pieces by spraying them with a fixative. Abrasive supports avoid or minimize the need to apply fixative. A pastel fixative is an aerosol varnish which can be used to help stabilize the small charcoal or pastel particles on a painting or drawing. However, fixative will dull and darken pastel's beautiful colors. It is also toxic, therefore it requires careful use. It cannot prevent smearing entirely without dulling and darkening the beautiful colors of pastels. For this reason, some pastelists avoid its use except in cases where the pastel has been overworked so much that the surface will no longer hold any more pastel. The fixative will restore the "tooth" and more pastel can be applied on top. It is the tooth of the painting surface that holds the pastels, not a fixative. Pastels must be framed under glass to prevent damage.
Glassine (paper) is used by artists to protect artwork which is being stored or transported. Some good quality books of pastel papers also include glassine to separate pages.
Pastel art in art history
The pastel medium was first mentioned by Leonardo da Vinci in 1495.
Artists such as Maurice Quentin de La Tour and Rosalba Carriera have been using pastels to create masterpieces as far back as 1703.
During the 18th century the medium became fashionable for portrait painting, used in a mixed technique with gouache.
In the United States, initially pastels only had occasional use in portraiture. However in the late nineteenth century, pastel (like watercolor) became more popular.