UART Tip #01: Oil Stain Underpainting with Karen Margulis


Never has watching paint dry been more fun. There is nothing shy about it. It’s bold. It’s rich. It is usually quite magical to watch. When I want to start a pastel painting with a bang this is the underpainitng technique I turn to…..Oil Stain Underpaintings!

It is simple to do. All you need is a few tubes of oil paints, stiff cheap brush and some odorless mineral spirits (OMS). You also need to use a surface that can get wet. I used UART 500 grit for today’s paintings. I love UART because it will take the abuse I give it. I can get the paper wet without it being mounted and it still won’t buckle! This underpainting technique is called oil stain because you are basically staining the paper with the thinned oil paint. If the paint is applied too thickly it will fill the tooth of the paper and you won’t be able to add much pastel.

As the oil paint dries the magic begins. The best underpaintings will result in interesting drips that look like root systems. It gives me something unexpected to respond to with pastel. It is a great technique to use when you want to loosen up and paint with more expression.

I don’t often do oil stain underpaintings because there is a bit of clean up involved. When I do, I often do serval underpaintings at once. Not only does this save clean up time….it is always good to practice underpainting techniques. The more you do….the better they will be.


Here are a few tips for Oil Stain Underpaintings:

  • Use a limited palette of oil paint. You are less likely to mix muddy color with only a

    Detail of painting. Notice the drips of the underpainting

    few colors. I only use alizarin crimson, ultramarine blue and cadmium yellow medium and mix the colors I need. I don’t use white since I want my colors to be rich and transparent. I don’t use black either but mix red and blue for a nice rich dark. You want nice thin and transparent color. Adding white will make it opaque and chalky. Black can be dull.

  • Make sure your paint is thinned with the OMS (I use Gamsol) I like for the paint to be the consistency of tea. If you can see your brushstrokes in the paint then it is too thick. If the paint is too thick it will be difficult to add layers of pastel.
  • If the paint is thin enough, the underpainting should dry in under an hour. I sometimes put my paper outside or near a fan to seed up the drying process.
  • Begin with the darkest paint. I like to mix red and blue for a nice dark purple. As the paint dries and the OMS evaporates, you will hopefully see interesting weblike drips occur. You can use water soluble oil paints but you won’t get the interest drips with the water.
  • When the underpainting is dry, it is time to add pastel. I use a very light touch and build up my layers… very slowly. I will leave areas of the underpainting untouched if I like the way it is working.

Karen Margulis PSA, IAPS-MS

Check out Karen Margulis’ blog, Painting My World, at