Mediums for Experienced Oil Painters

As NPS Live is rolling out to painters across the world I've found myself spending lots of time with painters who are new to oils, however that doesn't mean there isn't content here for you die hard oil painters! With that in mind I've dug into the archive to bring you this piece on one of our most requested topics - oil mediums.

If you'd like to see this in action check out our glazing masterclass on glowing skies or if you miss out on that one (there are only 3 tickets left at the time of writing ) keep an eye our for some more seriously technical courses we'll be offering over the summer.

Resinous Mediums and Glazing

If you’re reading this blog then you’ve most likely have an active interest in art, and must have wondered as I have, whether one should learn it properly or just trust one’s gut and go for it. If your art is sculpture, printmaking or ceramics then you’ll know that it’s unproductive to try these things without a bit of instruction. Yes, they are arts but manifestly also crafts. But painting? That’s not so cut and dried. You can paint successfully with no knowledge of the process whatsoever, and good luck to you. However you’ll find that a bit of know how about what paint can do will open up your creative options. So with that in mind, but with the caveat that craft cannot in itself become art, I’m offering you a short series of studio chats to facilitate your creativity. This time resins, mediums, glazing and all that. The top level idea this time by the way is indirect optical painting, so if luminous colour is your thing you’ve come to right lecture.

Optical Painting

Let’s start with a definition - or if you are near a major gallery a self guided tour. Most of the works of famous painters before 1874 were optical - which is to say they were painted in separate or indirect, stages, each affecting and being affected by the ones over or under it. Most of the paintings after Impressionism are not optical, but directly painted wet into wet. If you’re near a gallery (and the National is ideal), the best way to experience this is to walk from a room of Baroque oils to a room of Impressionist paintings. What was deep appears flat, what was nuanced and subtle, becomes bold , chiaroscuro gives way to creativity, texture and physicality. Now, if you are under 30, thinking ‘old master stuff isn’t for me’ pause to reflect that most of the great 21st century artists who stand out use old master inspired methods to make their contemporary paintings stand out from the crowd. Adrian Ghenie, Jenny Saville, Gerhard Richter, Peter

Doig, Cecily Brown - they are world class painters who ‘get’ the old masters. Got your attention?

Old Masters and Mediums

If we define contemporary art as being preoccupied with colour and visual design, we can say that traditional artists were similarly focussed on what mattered to them: optics. Optical painting means layered, which means painting in stages, and for that you’ll need to control how opaque your paints are, as well as how quickly and easily they can be layered up and worked over. If you follow that, then you have a working definition of what glazes, resins and mediums are and were for. Choose the right medium and you can make your paint glow, make it textured, enamelled, glossy or cloudy, make it dry in five minutes or five weeks. In short mediums are enablers of creative painting, and if you’re a creative visual artist that will be of interest to you.

Getting it wrong is right

Just before we move on to the studio mixing benches, we should set some expectations for success. One traditional school of thought sees painting as craft, and the use of media as a precise and controlled process where predictability, longevity and control is key. Ingres, Anagoni or David are artists who thought along those lines. While this has its merits, I prefer to think of mediums as opportunities to try creative things, explore new ideas and exploit the odd happy accident. Turner, Frankenthaler, Mitchell and Twombly were all artists in this vein. With that in mind here’s a short guide to the stuff I think you should get your hands on.

Glazing Mediums

A glaze is simply a mixture of paint with a translucent liquid binder of some kind. You can make a simple glazing medium by diluting oil paint with a bit of refined linseed, although this will leave a lot to be desired in terms of drying, so a varnish is more usual. Before you whizz out to buy a litre of wood varnish, you should know that a varnish is simply a resin in solution with a solvent, and that all resins and solvents have different working properties, such as colour, longevity, drying rate, turbidity and toxicity. This means that you should choose the right one for the job. To make a varnish which works hand in hand with your personal process, a blend of resins or substances which retard or speed drying might be combined, this concoction is termed a medium, and the reason that there are as many medium recipes as there are artists.

Traditional Resin Mediums

Personal preferences aside, all artists make their mediums from just a few common bases. In painting terms the traditional resins for oil medium making are Dammar, Copal and Mastic. These all offer a decent drying rate, translucency and gloss but require a strong solvent to dilute them, making them harmful to use over time. More than this they age poorly, causing paintings to darken and crack - not necessarily a defect to my mind - but admittedly not ideal if white abstracts are your thing. For these reasons most modern painters prefer synthetic resin mediums which are termed Alkyds. Alkyds perform more or less identically to natural resins, with the important difference that they require very mild solvents to put them in solution as mediums. This makes them much more pleasant and safe to use. I’m told that alkyds don’t age or discolour as natural resins do, but at my age I’ll need to take that on trust! Having spent a couple of decades splashing and sloshing both types around I can say that alkyds are easier to use, don't make you feel ill, and

should be your medium of choice, however their very predictable nature can make one paint predictably. So if you like to create expressive works which dry quickly then consider some traditional varnish mediums. They’ll create all kinds of drips, varnish rings, pulls and smears when handled expressively, and can be great aids to creative painting. Just work outside, or wear a half mask and keep your sense of humour if it all flakes off.


To glaze simply mix some tube oil with a medium and paint it over a dry surface - this can be a white gesso or a dry underpainting. It’s traditional to use translucent colours for glazing (check the tube), but as medium will always make a colour more translucent you can glaze with opaque colours, the results will just look cloudier .

Ten great tips for mediums

  1. Traditional mediums will smell of turpentine and dry quickly

  2. The strong solvents in traditional mediums mean your under painting should be absolutely dry

  3. Alkyd mediums dry more slowly but have a milder odour

  4. The weaker solvents in alkyd mediums mean you can work successfully if your underpainting is workably but not chemically dry

  5. Most mediums make paints more glossy

  6. Add a few drops of oil to mediums to retard drying time

  7. Add a bit of wax paste to mediums to make them cloudy (turbid)

  8. For stronger glazes try gel consistency mediums

  9. Glaze over your old work to give it new life, optical; effects can be transformative.

  10. Combine indirect with direct painting for the strongest visual effects.

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