How do they make Oil paint?
This is a simplified explanation of how oil paint is
made - the paint pigment is ground together with a binder, usually
linseed oil, although other oils are used depending on the pigment type.
Bees wax can be added, also driers and stabilizers.
By hand the process involves - first mixing the paint
pigment with the linseed oil to a crumbly mass on a glass or marble slab. Then a small amount at a time, is ground between the slab and a glass Muller (this is a round, flat bottomed glass instrument with a hand grip, like the one shown to the right). Pigment and oil are ground together 'with patience' until a smooth, ultra fine paste is
achieved, this is then placed into jars or metal paint tubes and labelled.
In commercial paint manufacture, years ago pigment and binder were ground together between special stones, like those used in an old flour mill. Today the paint pigment and binder, sometimes called a vehicle, are milled together on large
steel rollers. The resultant paint then goes through many tests before being put into the familiar paint tubes, a label is applied with full details of the contents and it then arrives on the shelves in an art shop.
The more important properties
of oil paint.
The information on the label will tell you a lot
about the paint:- the name of the pigment or pigments used, followed by
the pigment number i.e. Burnt Umber is PBr 7 - PBr
stands for Pigment Brown, PY Pigment Yellow and so on.
The label also tells you about the vehicle or binder the paint has been
made with, the vehicle is often Linseed Oil, although Safflower Oil is
regularly used for light colours.
The light fastness - this is shown by a star or number rating (usually
the higher the amount the more lightfast), e.g. a high lightfast
rating would indicate this colour is less likely to fade than a
lower rating when used under normal conditions.
Another symbol or wording is used, to state whether the paint is opaque, semi-opaque
or transparent. A caution notice if it is required.
to Colour Mixing
Oil Paint can be transparent,
translucent or opaque. If you are not sure
which, an easy way to check is put a dark line on a piece of
white card, use a brush to put a thin layer of paint across the
line. If you can see the line it's transparent, if the line isn't
visible it's opaque, if the line is indistinct but visible it's
translucent (often referred to as semi-opaque).
Another property of oil paint is its drying
rate. The earth colours (as they are often referred to) tend to dry the
fastest. These are usually made from iron oxide:- Burnt Umber, Burnt
Sienna, Raw Umber, Raw Sienna, Light Red, Mars Red, Mars Violet and Mars
Orange. These are often applied at the beginning of a
painting, their fast drying makes then good for underpainting.
The slow dryers tend to be Titanium and Zinc White, Alizarin Crimson,
some Yellows, Green Earth and Ivory Black. These are often applied
towards the end of a painting, this helps maintain the 'fat over lean'
principal more information on this can be found on the
to Colour Mixing
Paint has three other properties concerned with it's colour:- 1) Hue; 2)
Value; 3) Chroma, this is covered on the Colour
Oil Paint can also be thinned, usually with a solvent like Zest-it or
painting medium, this gives different qualities to the handling of the paint
and the way it behaves after being applied to the canvas. It can also be used 'as is' straight from the tube,
especially where texture is needed. Some people also add wax paste to the paint, this again will give a
different look and feel to the paint.
Copyright© Jacqui Blackman 1999