Pastels are made from pure finely powdered pigments which are ground into a paste with water and a gum or methyl cellulose binder. This paste is rolled into sticks and then allowed to dry. Pumice may be added to make the pastel abrasive to create more tooth on the paper surface. To create paler shades, chalk is added to the pigment. They can be used in combination with other dry media. These include charcoal, coloured conte crayons, and pastel pencils. Pastels will not cover graphite pencil lines.
An excerpt from the Heilbrunn Timeline of Art History - The Eighteenth-Century Pastel Portrait says 'Pastels have always been praised for the freshness of their colors, at once both brilliant and subtle. Although we now recognize their fragility, in the eighteenth century pastels were often thought more durable than oils, as these vibrant colors were less susceptible to damage by light (oils often faded or yellowed with age). Pastel, too, afforded the artist a richer interplay between medium and support than oils did. Pastel paintings were commonly executed on blue paper mounted on canvas, not only because this was the thickest paper available in the eighteenth century, but also because of the chromatic advantages it offered as the pigments of the pastel picked up and interacted with the blue background' read in full.
Paper for Pastel Drawings
Textured paper with enough tooth to retain the medium is the best used for pastel or charcoal drawings. The texture is formed on a cylinder mould machine by pressing the paper fibres between the cylinder mesh and the marking felt. This surface texture is known as a chain and laid line surface. A good choice for pastel drawing is Canson Ingres or Canson Mi-Teintes paper. The finished drawing should be protected either under glass (not touching the surface) or between sheets of Glassine paper to stop the pastel from smudging. There are a variety of spray fixatives which should be applied carefully to ensure the colours are not effected.
Soft pastels contain a higher proportion of pigment giving excellent colour which is readily blended. These pastels tend to leave a high dust residue which needs to be intermittently blown off the drawing to prevent unplanned smudging and marks.
Water soluble Pastels
These soft pastels contain a water-soluble component. This allows the colours to be thinned out to an even, semi-transparent consistency using a water wash. The colours are easily blended with water applied by brush.
The higher proportion of binder in hard pastels allows fine detail drawing. The colours are less brilliant than soft pastels. They are ideal for adding accents or outlines to soft pastel drawings, and for preliminary sketches.
The pigment is mixed with a non-drying oil and wax binder making a soft, buttery consistency which fills the grain of the paper. The intense colours can be thinned with turpentine and do not require a fixative.
Browse the large range of pastels available from George Weil to find out more.
Nicky Nikolov's YouTube film: 'Drawing a Girl Portrait in Soft Pastel'