Pastel


A pastel is an art medium that consists of powdered pigment and a binder. It can exist in a variety of forms, including a stick, a square, a pebble, and a pan of color, among other forms. The pigments used in pastels are similar to those used to produce some other colored visual arts media, such as oil paints; the binder is of a neutral hue and low saturation. The color effect of pastels is closer to the natural dry pigments than that of any other process.
Pastels have been used by artists since the Renaissance, and gained considerable popularity in the 18th century, when a number of notable artists made pastel their primary medium. The medium has been especially popular in French art. It has often been used for portraits, but can be very effective for other subjects, such as landscape paintings. Compared to oil paint it is quick and straightforward to use, with some of the advantages of drawing.
An artwork made using pastels is called a pastel. Pastel used as a verb means to produce an artwork with pastels; as an adjective it means pale in color.

Pastel media

Pastel sticks or crayons consist of powdered pigment combined with a binder. The exact composition and characteristics of an individual pastel stick depend 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 and gum tragacanth. Methyl cellulose was introduced as a binder in the 20th century. Often a chalk or gypsum component is present. They are available in varying degrees of hardness, the softer varieties being wrapped in paper. Some pastel brands use pumice in the binder to abrade the paper and create more tooth.
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. The drawing can be readily smudged and blended, but it results in a higher proportion of dust. Finished drawings made with soft pastels require protecting, either framing under glass or spraying with a fixative to prevent smudging, although fixatives may affect the color or texture of the drawing. While possible, it is not recommended to use hair spray as fixative, as it might not be pH neutral and it might contain non-archival ingredients. White chalk may be used as a filler in producing pale and bright hues with greater luminosity.
  • Pan pastels: These are formulated with a minimum of binder in flat compacts and applied with special soft micropore sponge tools. No liquid is involved. A 21st century invention, pan pastels can be used for the entire painting or in combination with soft and hard sticks.
  • 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. Hard pastels are traditionally used to create the preliminary sketching out of a composition. However, the colors are less brilliant and are available in a restricted range in contrast to soft pastels.
  • Pastel pencils: These are pencils with a pastel lead. They are useful for adding fine details.
Image:Commercial pastels.JPG|thumb|right|200px|Commercial oil pastels
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 dense and fill the grain of paper and are slightly more difficult to blend than soft pastels, but do not require a fixative. They may be spread across the work surface by thinning with turpentine.
  • Water-soluble pastels: These are similar to soft pastels, but contain a water-soluble component, such as polyethylene glycol. This allows the colors to be thinned out to an even, semi-transparent consistency using a water wash. Water-soluble pastels are made in a restricted range of hues in strong colors. They have the advantages of enabling easy blending and mixing of the hues, given their fluidity, as well as allowing a range of color tint effects depending upon the amount of water applied with a brush to the working surface.
There has been some debate within art societies as to what exactly qualifies as a pastel. The Pastel Society within the UK states the following are acceptable media for its exhibitions: "Pastels, including Oil pastel, Charcoal, Pencil, Conté, Sanguine, or any dry media". The emphasis appears to be on "dry media" but the debate continues.

Manufacture

In order to create hard and soft pastels, pigments are ground into a paste with water and a gum binder and then rolled, pressed or extruded into sticks. The name pastel is derived from Medieval Latin pastellum "woad paste," from Late Latin pastellus "paste." The French word pastel first appeared in 1662.
Most brands produce gradations of a color, the original pigment of which tends to be dark, from pure pigment to near-white by mixing in differing quantities of chalk. This mixing of pigments with chalks is the origin of the word pastel in reference to pale color as it is commonly used in cosmetic and fashion contexts.
A pastel is made by letting the sticks move over an abrasive ground, leaving color on the grain of the painting surface. 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

Pastel supports need to provide a "tooth" for the pastel to adhere and hold the pigment in place. Supports include:
  • laid paper
  • abrasive supports
  • velour paper suitable for use with soft pastels is a composite of synthetic fibers attached to acid-free backing

    Pastel on canvas

Pastel painting on canvas is a relatively uncommon technique. It involves applying pastel chalks to a primed canvas. This technique was traditionally used for larger works or to achieve a more painterly effect. As early as the 18th century, individual artists began experimenting with using canvas as a support for their pastel works. Early examples include portraits by Rosalba Carriera, who used primed canvas as well as paper. Her aim was to achieve a more stable surface and increased colour intensity. Jean-Étienne Liotard also experimented with using pastels on materials other than paper, such as canvas and wooden panels, to create smooth, painterly surfaces.
Large-format pastel portraits by the 18th-century French artist Maurice Quentin de La Tour have been preserved. In these works, either pastel colours were applied directly to the canvas or the drawings were mounted on it for permanent display. Technical and artistic experimentation in the 19th century led to a resurgence in the popularity of pastel painting on canvas. Edgar Degas played a central role in this, frequently using pastels on canvas and combining them with oil and tempera. The canvas enabled him to make repeated revisions and apply thicker layers of pigmented colour. Pastels on canvas were also employed in the Symbolist and Expressionist movements. Edvard Munch used pastels on canvas and in mixed media to achieve an intense, two-dimensional effect. Similar techniques can be seen in the work of Odilon Redon, who used both canvas and paper as a medium for his coloured pastel pieces. In contemporary art, pastels on canvas are primarily used in mixed media. Modern acrylic or chalk primers improve the adhesion of the pigments to the canvas surface. Artists such as Wolf Kahn use pastels on canvas, particularly for landscape paintings, combining elements of drawing and painting.

Protection of pastel paintings

Pastels can be used to produce a permanent painting if the artist meets appropriate archival considerations. This means:
  • Only pastels with lightfast pigments are used. As it is not protected by a binder the pigment in pastels is especially vulnerable to light. Pastel paintings made with pigments that change color or tone when exposed to light suffer comparable problems to gouache paintings using the same pigments.
  • Works are done on an acid-free archival quality support. Historically some works have been executed on supports which are now extremely fragile and the support rather than the pigment needs to be protected under glass and away from light.
  • Works are properly mounted and framed under glass so that the glass does not touch the artwork. This prevents the deterioration which is associated with environmental hazards such as air quality, humidity, mildew problems associated with condensation and smudging. Plexiglas is not used as it can create static electricity and dislodge the particles of pastel pigment.
  • Some artists protect their finished pieces by spraying them with a 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. It cannot prevent smearing entirely without dulling and darkening the bright and fresh colors of pastels. The use of hairspray as a fixative is generally not recommended as it is not acid-free and therefore can degrade the artwork in the long term. Traditional fixatives will discolor eventually. There are also casein-based fixatives available premixed in a pump misting bottle or as concentrate to be mixed with alcohol. They are non-toxic and do not darken or dull pastel colors. However, they take a little longer to dry than conventional spray fixatives between light layers.
For these reasons, some pastelists avoid the use of a fixative 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. Abrasive supports avoid or minimize the need to apply further fixative in this way.
Glassine 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.