Mediums – the most misunderstood word in oil painting. There are 3 components we use when painting in oils. All 3 are often referred to as “mediums”. Here is a description of each one, when and how they are best used:
Medium #1: Solvents LEAN
Medium #2: Oil Paint NEUTRAL
Medium #3: Oil Painting Mediums FAT
Solvents (often referred to as paint thinner or brush cleaner) are used for thinning paint and preliminary brush cleaning. These solvents are either turpentine or mineral spirit (petroleum products) based. The mineral spirit products are marketed under a variety of manufacturer names, such as: Gambsol (Gamblin product); DaVinci; OMS; Masterpiece; etc. Turpentine products are usually marketed as such. Be aware that Turpenoid is NOT a turpentine product. Acrylic paint can be successfully used UNDER oil paints to tone a canvas and/or set in images. It is strongly suggested that acrylics not be applied thickly or built up into thick layers, as it doesn’t dry as quickly as previously thought and can “snap” oil layers that might dry faster (above the acrylic layers).
One of the main uses for a solvent is to thin down paint out of the tube when applying an initial layer of paint on a canvas. I have used the word “scrumbling” for years (it was told to me) to describe this process. It is not to be confused with the word “scumbling” which is a different technique. Using scrumbling approach gives me time and opportunity to explore color and value choices (referencing my thumbnail sketch for the composition’s value design).
Oil paints (straight out of the tube) consist of pigment mixed with oil, usually vegetable in nature. This is the first introduction of “fat” over “lean”. Once paint thinned with solvent has been applied, the next step is applying paint either directly “out of the tube” or mixed with a painting medium (below).
Painting mediums are added to any oil paint in order to change the paints’ longevity, malleability and viscosity. There are many, many varieties of mediums: those that make the paint runnier; make the paint thicker; make the paint dry faster; make glazes and so on. These mediums are made with a wide variety of oils: walnut, poppy, linseed, stand, etc. For expert information on how to safely use a medium (and what choices to make), I suggest you start with Ralph Mayer’s Book “The Artist’s Handbook of Materials and Techniques”. Available in your local library (if not, ask for it) or at Amazon.com.
Paint can be applies with bristle and/or natural hair brushes as well as palette knives. Brushes come in bright, flat, filbert and round shapes.