Michael Harding Oleo Impasto Medium (PM7) is a gel made from fumed silica and linseed oil which imparts great luminosity, particularly with transparent colours. You can add it with a brush or knife to achieve extra body. In this Artist Review of the Month, Joanna Sheldon shares how she uses the medium in her painting practice, and what she loves about it.
Michael Harding Oleo Impasto Medium
by Joanna Sheldon
I love this stuff. I use it in part to avoid solvents, though it has far more value than just that. Used straight it can sit like a jelly on the palette (very practical, especially for plein air painting), and can be lifted with a palette knife, but turns to a kind of liquid when you press a brush into it, making dipping into solvent or solvent/oil largely unnecessary – a huge advantage when working in the studio.
Mixed with paint, like all gels it has the effect of lifting the paint off the canvas so that light can pass through it, giving the colours a glow not attainable with pure paint.
I often make my own paints, usually mixing or grinding them with linseed oil, but for glazing purposes pigment powders can be mixed directly into the Michael Harding Oleo Impasto Medium. For a heavier mixture I add the Oleo Impasto to a medium I’ve been using for years: 50/50 Gamblin Neo Megilp + Gamblin Cold Wax. Neo Megilp and Cold Wax together dry to the touch reasonably fast but remain open forever. This has the advantage that I can use solvent on an old rejected painting to wipe away paint revealing lower layers, that I can make part of a new painting on the same canvas; it has the obvious disadvantage of preventing the formation of a protective hard film of oil. The Oleo Impasto Medium allows for a similar texture without the use of wax. To stiffen the Oleo Impasto Medium without much loss of transparency I add either finely ground chalk or marble dust to the required consistency.
I occasionally blend paints that are too dry with a bit of stand oil or sun-thickened oil. In this way I both avoid poisoning the air with solvents and give myself a lot of different textures to choose from while painting.
I keep a small jar of walnut oil on the side with which to clean hands and brushes as I go along – Michael Harding Oleo Impasto Medium cleans off easily, and when I’m done for the day, the brushes go into a container of walnut oil, a wide-mouth jar laid at an angle in a wide bowl, so as not to harm the tips of the brushes.
About Joanna Sheldon
I grew up in a family of painters, and have been drawing since I was two. We travelled a lot, especially in countries around the Mediterranean, so that’s my painterly home, though I’ve lived in England for the last couple of decades, with occasional escapades to southern France and Italy to recharge the batteries.
Aside from the occasional political poster my work has no intent, is not deliberately about anything. Art, though it can make a statement, is for me a refuge from words. As much as possible textures, tones, gestures, colours, and light are what I deal in.
I’m a materials person, and enjoy researching mediums and pigments, and grinding my own paints, especially oils, which are my primary interest. The physical handling of oil paint, with palette knife, brush, fingers, and fabric, seems to offer almost endless possibilities. I have exhibited and sold my work in the USA, France, and the UK.
Further Reading
3 Ways to Thicken Your Oil Paint for Impasto Techniques
Making Beeswax Impasto Medium for Oil Painting
Choosing a Clear Primer for Oil Painting
Mediums Are the Key to Water-mixable Oil Paints
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