- Leave a half-inch to 1-inch border on your pastel artwork. This leaves room for the artwork to be matted properly, it also allows the edges of the paper to be taped to a mount board without getting tape on the artwork.
- When storing the pastel painting, use an acid-free artist tape to carefully tape the corners of the pastel painting to the center of a sheet of acid-free foam board (cut to size). Next, lay a sheet of glassine over the artwork. An acid-free artist tape can be used to secure the glassine to the foam board.
- When shipping pastel portraits, use glassine (archival, museum-quality barrier paper) to protect the surface of your art; gassine does not attract loose pastel particles.
- If shipping or storing pastels, place a second sheet of acid-free foam board on top of the pastel artwork. The artwork should resemble a "foam sandwich"(Note that recommended materials are acid-free.).
While I have just recently begun painting portraits in oil, I am familiar with oil painting (abstract works). Compared to oil painting, pastels require far less time and fewer tools. While most pastels are executed on paper, Jean Étinne Liotard (Swiss, 1702-1789) used vellum for portraits of royal sitters. Vellum is relatively strong and coarse and thus well suited to withstand rubbing with pumice, a technique that artists used to produce a weak bond, or tooth, to hold the pastel portrait to the support. Today, papers with this "tooth" surface are readily available.
The pastels I created were blended with my fingers, though many pastelists use stumps - or tight spirals of paper or leather - to spread the pastel powder. Historically, portraits were executed with dry pastel, with the artist blending (stumping or "sweetening") the color into a smooth continuous mass without evidence of individual strokes. Sometimes a network of discrete strokes can be utilized which the eye optically blends.
While I have not yet experimented with blending with turpentine (applied with a brush), many artists recommend this technique for blending as opposed to using your fingertips, which can go almost instantly numb from utilizing them as a tool.
The versatility of pastels makes them an attractive medium to consider. Not only do they offer a velvety effect, but they can be mixed with other mediums, such as oils or watercolors. In Rosalba Carriera's Young Woman with a Pearl Earring, the pastel tip was wetted and then applied thickly to create an impasted effect comparable to oil, as seen in the lace details of John Russell's Portrait of Mrs. Robert Shurlock and Her Daughter Ann.
- Pastels should always be framed and glazed (to best preserve them).
- Most acrylic sheeting is not satisfactory to glaze pastels because its static charge will attract pastel particles, a problem that is exacerbated when the plastic is rubbed.
- To protect my fragile artworks, shatterproof glass with an Ultraviolet (UV) barrier is my best choice.
- Pastels are occasionally glazed with AR acrylic sheeting, but conservation experts are uncertain of this material's long-range properties (such as deleterious off-gassing, which is common to many plastics as they age and deteriorate). Still, artists are mavericks in the sense that they are constantly experimenting with new materials and mediums. Thus, if you feel comfortable utilizing this sheeting, go right ahead. I wouldn't recommend utilizing it to preserve an eighteenth-century pastel portrait, but that's me.
- Original eighteenth-century glass does not have a UV barrier, they are protected from fading and color alteration by maintaining low light levels, covering the frame or closing curtains when not being viewed.
- Also, nearby windows can be coated with a UV film.
- To prevent dust from entering into the frame, a seal made of strips of paper can be applied to the back of a framed pastel.
- Keep the room in a range of 68 to 72 degrees Fahrenheit and 48 to 52 percent relative humidity. High humidity can provoke staining; low levels can lead to desiccation of the support.
- This can be reduced by cushioning crates with ethafoam, or, if the artwork is traveling a short distance, wrapping the composition in bubble wrap with the bubbles facing outward.