This article reviews some of the more popular oil painting mediums, their purpose, and some advice on how best to use them. The purpose of adding these substances to your oil paints is to change the behavior of the paint during application and affecting results after the painting dries. Behavior describes the way the paint comes off the brush and glides on the surface, how it covers either the surface or succeeding layers, and precisely how it feels as you apply it.
Brands of paint act differently and mediums help you control the paint the way you want it to behave as you use it. Some paint manufacturers –and here I’m only referring to the artist grade paints rather than the student grades–are stiffer straight out of the tube. Student grades have less pigment and much more fillers like extra oil and simply don’t perform well. If you use those paints that are stiffer from the tube, but want more flexibility in the way they handle, or behave, you will require a medium. If you want brush strokes apparent in your final painting, a lighter paint functions better. Including a refined linseed oil in tiny amounts until it feels right to you will promote the paint to level out and reveal less strokes. Less Rat Poop and more strokes will reveal. If you want an impasto technique (think Van Gogh), Gamblin Alkyd Gel thickens paint well. Always remember to never put a faster drying layer on a slow drying layer of paint.
Glazing mediums permit you to apply thin layers of paint and build colour and luminosity by having the viewer’s eye blend the colours rather than mixing the paint on the palette or canvas. Using a medium like Liquin by Winsor & Newton speeds drying time while thinning the paint allowing layers to be constructed without waiting a couple of days for each layer to dry before you apply another layer. Additionally, there are glazing mediums available like A conventional medium used for decades by many painters is refined linseed oil, a bit of solvent (typically mineral spirits), plus a bit of stand oil, and a touch of Japan or Cobalt Drier These components are blended in a balance to achieve your desired results, like quicker drying time, more shine, etc.. ) Stand oil is merely a thicker linseed oil which can decrease brush strokes and increase gloss. Adding Damar varnish to your mixture also adds gloss and can accelerate drying time. Damar varnish is made from tree resin and alkyd is a form of synthetic resin.
There are a number of mediums and I recommend you try several until you find what works best for your style of painting.