Oil Pastels vs Soft Pastels: Which Should You Choose?

Oil pastels and soft pastels are sold side by side, cost roughly the same and look almost identical in the box. They are not variations on one medium. They are built from different binders, they behave differently on paper, they need different surfaces, and most of the frustration beginners have with pastel comes from buying one when they wanted the other.

The difference is the binder

A soft pastel is pigment held together with a small amount of gum binder, pressed or rolled into a stick and dried. The binder is there only to stop the stick falling apart. What ends up on the paper is nearly raw pigment, held by the tooth of the surface rather than by any glue.

An oil pastel is pigment ground into mineral wax and a non-drying oil or synthetic medium. It never dries, never forms a skin and never becomes raw pigment on the surface. It stays a soft, greasy film that you can push, layer, scrape or dissolve months after laying it down.

Everything else follows from that one difference.

How they behave

• Blending. Soft pastel blends dry, with a finger, a torchon or a brush, and the blend is physical: you are moving loose pigment around. Oil pastel blends by smearing, or by dissolving with white spirit or turpentine, which turns it into something much closer to painting.
• Layering. Soft pastel layers cleanly until the tooth of the paper fills up, at which point nothing more will stick. Oil pastel layers almost indefinitely, but the lower layers stay soft and can lift into the upper ones.
• Detail. Neither is a precision medium, but a soft pastel edge can be sharpened with a hard pastel or a pastel pencil. Oil pastel sharpens with a blade or by scraping back through the layer, a technique called sgraffito.
• Dust. Soft pastel produces a lot of it, which is a real consideration in a small room. Oil pastel produces none.
• Warmth. Oil pastel softens in the hand and softens a lot in an Indian summer. Working in a cooler room, or chilling the sticks briefly, restores control.

Surfaces

Soft pastel needs tooth. Smooth cartridge paper will take one or two layers and then refuse. Use a dedicated pastel paper, a sanded pastel board or a textured watercolour paper; the rougher the surface, the more layers it will hold.

Oil pastel is far less fussy. Paper, card, board, primed canvas, wood and even glass all work, because the wax grips rather than lodging in the tooth. Oil pastel on unprimed paper will eventually stain it with the oil content, so prime with gesso if the piece matters.

Fixing and finishing

Soft pastel is fixed with a pastel fixative, and the honest advice is to fix between layers rather than saturating the finished surface. A heavy final coat darkens the work and flattens the vibration between tones, which is the main thing soft pastel has going for it.

Oil pastel cannot be fixed in the conventional sense, because there is nothing to dry. A specialist oil pastel fixative sprayed eight to ten days after finishing keeps dust off the surface without hardening the colour. Framed work should be glazed with a spacer so the glass never touches the surface. The same applies to soft pastel, for a different reason: contact will smear it.

Which one to buy

Buy soft pastel if you want the luminosity of dry pigment, work from drawing rather than painting habits, like blending with your hands, and have somewhere the dust does not matter.

Buy oil pastel if you want something closer to painting, work in a sketchbook or on the move, dislike dust and fixative, or want to work on canvas, board or wood as readily as paper.

If you are buying for a child or a classroom, oil pastel is the practical answer: no dust, no fixative, no fragile surface.

What to look for in a set

Pigment load is what separates a student stick from an artist one. A cheap oil pastel is mostly wax with a little colour, so it skids over the paper and leaves a thin, waxy stain. A good one lays down opaque colour in a single pass.

On the soft pastel side, the test is how little pressure it takes to make a mark. Uncompressed, air-dried sticks crumble onto the paper almost on contact; harder sticks are useful for edges and underdrawing but will not give the velvet surface people buy soft pastel for.

Sennelier oil pastels are the reference point for the medium, made in 1949 at the request of Henri Goetz so that Picasso could work on any surface without the colour cracking or fading. Sennelier extra soft pastels sit at the soft end of the dry range, uncompressed and air dried. Mungyo covers both families at a lower price, and Cretacolor and Koh-I-Noor are worth looking at for harder sticks and pastel pencils to draw into soft pastel work.

A sensible first purchase

A 24-stick assorted set in whichever family suits you, plus the right surface, will teach you more than a 100-stick box on the wrong paper. Themed sets, landscape or portrait, are worth buying second, once you know which tonal range your subjects actually need. Half sticks are the better value in soft pastel: identical composition, sturdier in the hand, and roughly twice the number of colours for the money.

Browse all oil pastels and soft pastels, or the papers and pads to work them on. Stationerie has been supplying artists from Kolkata for 25 years and ships across India.