Q. I recently found a set of pastels that I’ve had for longer than I can remember, and then I discovered that they’re oil pastels, which I’m not familiar with. Are they compatible with other (non-oil) pastels, and do the same application techniques apply? Do they have any different requirements for such things as supports, priming and fixing? And last, could the sticks I have be too old to use?
A. Oil pastels offer you a great new painting experience if you’ve never tried them before, and I think you’ll find that they’re not difficult to use. When it comes to mixing media, they’re compatible with other pastels and with any oil paint, too. In fact, I’ve seen oil pastels used with just about all the other materials at our disposal, including transparent watercolor, gouache and acrylic emulsion paints. I’d encourage you to try as many different techniques as you like, but here are a few guidelines to consider as you proceed.
First, it’s generally wise to avoid getting carried away with the application of oil pastels, especially in mixed-media works. If they’re applied too thickly—and, believe me, it’s such a luscious painting medium that you’ll want to pile on the color—then you may find that your work either doesn’t dry properly or is too susceptible to cracking and flaking. As in regular oil painting, it’s best to keep your applications thin and relatively simple until the work nears completion, and then use some impasto for emphasis.
If you think of oil pastels as a colored drawing medium rather than a thick, robust paint, the support and priming requirements are relatively simple. Use a good quality paper (“acid-free,” “pH-neutral,” “archival,” etc.) and choose whatever surface finish is appropriate to your style of work. But if you want to make oil pastel pictures that are elaborate and heavy-handed, then it’s better to mount the paper on a rigid backing such as hardboard or plywood. Use an acrylic emulsion gel medium for this, as both an adhesive and an acid barrier for the wood, and then consider sizing the paper with an acrylic emulsion matte medium slightly thinned with water.
The reason for using the sizing is to protect the paper from the drying oil content of the oil pastels. Many contain an oil that dries by oxidation (linseed oil, for example), and this process can leave unsized paper stained and brittle. Another way to minimize this risk is to use oil pastels that contain a larger proportion of wax (usually beeswax or paraffin) than oil in the vehicle. Some of these have a nondrying oil (like a mineral oil) that hardens under the influence of the wax. But because these types of pastels dry by hardening and not by oxidation, they don’t develop as hard a surface as the other types and can be susceptible to surface scratches and dents.
When combining oil pastels with regular chalk pastels you’ll still have to be cautious about staining and embrittling the paper, but you should also know that the oil pastels vehicle will change the “refractive index” of the chalk pastels. This means that if your chalk pastels were manufactured with the addition of white chalk as a lightener, then oil pastels will make them translucent. If the sticks were lightened with white pigment instead of white chalk, then the oil pastels will make them darker. You’ll have to experiment to see which is the case and what effects you can achieve.
Remember, too, a couple of guidelines for mixing media in general. The more complicated the physical makeup of a picture, the more likely it is to have structural problems in the future. Increasing the number of layers or the number of components with differing physical characteristics increases the risk of cracking, flaking or other material damage as the work gets older. Also, as an aesthetic concern, one medium ought to be dominant in the composition. That is, if the painting is primarily in oil, then additions of oil pastel should be kept to a minimum, perhaps as accents or reinforcements of a particular element. Keep the pictorial idea, not the techniques, in the forefront.
Finally, you ask if the sticks you have might be too old to use. It’s possible that they are, and the manufacturer has probably changed the formula since your sticks were made. Because oil pastels are a nontraditional medium, there are no industry-wide standards for their longevity and it’s therefore hard to know just what you’ve got. You could probably have some fun and learn a few things by experimenting with them, but if you want to use oil pastels for a painting that will last, I’d recommend that you take the safe route and buy a new set.~Jack Hines
Learn more about oil pastel techniques in this FREE download from The Artist’s Magazine’s Mediapedia (an encyclopedia of art media) and a bonus article, you’ll learn the basics of painting with oil pastels. Mediapedia: Oil Pastels by Greg Albert includes FAQs about this medium, must-have tools, safety and cleanup methods, an explanation of oil pastel chemistry, and more! As a bonus, we’re including a special “Competition Spotlight” article by oil pastelist George Shipperley.