Q&A for How to Blend Oil Pastels

Use a paper that’s okay for oil paint. You could also use cardboarding that you prepare with a clear matte gel. Or you can put some acrylic gesso on the paper you’re using. The point is to create a barrier so that if you use turpentine, it doesn’t eat away at the paper.

Apply dark colors first, then apply light colors. Applying light colors first will not work because there will be a harsh line between the colors. By applying dark first, you can create a smooth transition between the colors.

Yes, I have done this before myself with good results.

Yes. You can always blend with as many colors as you want.

Hairspray is used to set chalk pastels. Oil pastels do not produce dust like chalk pastels, so hairspray will not work in the same way. You will make a sticky smeary mess.

You can use almost any oil product, but some work better than others. Boiled linseed oil is excellent in helping to increase the drying time and hardness of the pastels, while unboiled oils take longer to dry. And a brush is a wonderful tool to blend. If you want to get into small areas and fine details, use a small brush; to blend larger areas increase the brush size. Remember to clean your brush with a mineral spirit or paint thinner, since oil is water-soluble, or else some pigment or oil may remain on your brush and affect your next project.

No, you use hairspray when you have a chalk drawing so that it doesn't smudge.

I use either watercolor or primed canvas, depending on what I intend to do with the finished piece. What you are looking for is a little texture or tooth for the pastels to grab onto (but not essential, read on). You can always apply some gesso to smooth card, and that will work just as well; just be aware that you are going to apply a wet medium, and this could easily warp light card and paper. I also use them on parchment and vellum to color my designs. This works well, but I do prefer soft pastels and some hairspray, as they are easier to work and achieve a softer look.

Oil is non-soluble in water. Since oil pastels are oil-based (which is why their texture is thick and creamy), they are non-soluble in water.

Yes, since paintings should always follow the "fat over lean" process to avoid cracking. Oil crayons are going to sit on top of your paint with no issues.