|
What
is paint and what is the difference between each type of paint?
The
brief technical bit!
Paint
is a dispersion of pigments, resins and fillers in a liquid
carrier. By varying the basic ingredients the different types of
paint can be created.
Oil
Paints
Oil
paints as the name suggests contain oil. This is usually a
natural vegetable oil such as linseed or a synthetic hydrocarbon
made from oil.
The
oil is the carrier used for the pigment and resins (alkyd). The
pigments provide the colour which can be in the form of a
soluble dye or an insoluble powder finely dispersed in the
liquid. The various colours are produced from one or several
pigments mixed together. By varying the different amounts, not
only the different colours, but different shades and hues can be
produced.
The
resin is dissolved in the oil and acts as a binder for the
different ingredients and to, and also binds the paint to the
surface that it is applied to.
When
the liquid evaporates after application, the resin and the
pigments remain and form a skin which sticks to the painting
surface.
Acrylic
Paints
Acrylic
paints are similar in make-up to oil paints, i.e. they are
similar in appearance and contain a liquid carrier, pigments and
resin. However, the liquid used is water.
The
resin is not the same type as in oil paints, because it has to
combine with water. The acrylic resin does not dissolve in the
water but forms an emulsion (forms globules). When the water
evaporates the globules of resin stick together to form a skin.
The pigments used must also combine with water and so are
chemically different than oil pigments.
Watercolours
Watercolours
consist of pigments, filler and water if they are in liquid
form, or just pigment and filler in they are solid. As they have
no resin component to bind the pigments and form a skin, they
rely on the surface they are applied to, to be absorbent. A
filler is a fine powder which can be used as a carrier for the
pigment and provides texture/body.
Pastels
Pastels
are a solid paste form of water-colour. Far less water is used
in their manufacture (when compared with liquid paints), and
water soluble binders are used to maintain their solid paste
form. Oil based pastels are similar with far less oil used than
used in making oil paints.
What
are the practical differences between the different types of
paints?
Oils:
dry slowly allowing time to work and to blend colours. The
temperature of the air you are working in, and the proportion of
thinner used dictates the drying time
can be used to produce texture by building layers
once dried sufficiently, can be over-painted without disturbing
underlying layers
rich, deep colours which maintain their intensity when dry, so
can be left unfinished and returned to later without a change of
colour
can be used thickly or in thin, smooth washes increasing the
scope for different painting techniques
colours are resistant to bleaching by sunlight and surfaces can
be cleaned of dirt with methylated spirits
completely water proof and resistant to the elements
require brush cleaner/white spirits to clean brushes
usually applied to non absorbent surfaces including board, wood,
coated paper and canvas
Acrylics:
dry fast but still allows time to work and to blend colours. Can
be a disadvantage when working with thick applications in hot
environment
less viscous than oils so easier to mix but tend to produce less
texture and brush strokes
can be mixed with water or other mediums/gels which are
compatible with water
can be used thickly (impasto) like oils, or in thin washes, like
waterclours, so can be used on both absorbent and non absorbent
surfaces
once dried can be over-painted without disturbing underlying
layers
water resistant when dry
colours dry darker than when applied so can give problems with
colour matching if left
less resistant to sunlight that oils, surfaces can be cleaned of
dirt with methylated spirits
requires water to clean brushes, but can give difficulty if
brushes dry prior to washing
Watercolours:
mixed with water giving transparent colour
dries fast and requires pre-wetting of the surface in hot
environment
strong tendency to bleed so good for general wash techniques but
can be difficult for fine definition
transparency makes it hard to rectify or hide mistakes
colours dry lighter than when applied so can give problems with
colour matching if left
no white in watercolour painting, the white comes from the paper
you are working on. So can be difficult to produce prominent
white high-lights without preplanning or masking
paint can be lifted off by rewetting so can be useful in some
techniques, but can be difficult to use in wet conditions or in
hot/dry conditions where rewetting is necessary
brushes are cleaned easily with water and paint is reusable when
dry by adding water
colour intensity is less when compared with other media and
tends to bleach in direct sunlight. Problems with
dis-colouration to the support and the media can occur in damp
conditions
very difficult to clean the surface without damage so has to be
protected from the elements under glass or other suitable
material
Pastels:
colours are mixed on the paper/support by over-laying or
blending so no drying time
easily used and require no brushes
oil based pastels can be thinned and blended with turpentine, or
scrapped off to reveal colours underneath, known as sgraffito
a wide range of colour are available, however, usually a greater
range of colours are required to create a picture when compared
with other media
different brands and pigments tend to vary in softness so
difficulties can arise when obtaining supplies from varying
suppliers
soft pastel works tend to be liable to smudging and the colour
coming off the support unless precautions such as fixatives or
mounts are used to keep the surface away from frame glass
Other
considerations:
Cost:
Watercolours are the cheapest to set yourself up with and most
budding artists start this way. However, watercolour requires
different techniques to other media and can restrict development
acrylics are not as expensive to buy as oils and can bridge the
gap between oil and watercolour
oils are more expensive to buy initially; however a little goes
a long way when painting thinly. Several paintings can be
produced from a single tube of each of the base colours
Hazards:
Oil
Paints:
Some
people are put off by oil paints because of the solvents
involved; they may be allergic to the solvents or may not want
solvents lying around when young children are about. However,
oil paints themselves usually contain linseed oil as the carrier
which has low odour and is essentially non toxic. The pigments
themselves are bound by the oil and are not available to cause
hazards. White spirits and turpentine used as thinners or brush
cleaners are flammable and should be used sparingly. However the
volume used is very small and the hazards are many times less
when compared with the use of domestic household paints. Saying
this, low odour versions of paints are available.
Acrylics:
Acrylics
are the least hazardous as there are no solvents used and the
pigments remain bound in the paint.
Watercolours:
Can
be hazardous if traditional pigments are used because they are
not bound by resin and dry to a fine powder. However the
quantities used are so small that hazards are very minimal.
Pastels:
Similar
to watercolours, however soft pastels can produce a lot of dust
so care should be take to minimise the amount you inhale. For
example, do not blow on your work to remove loose pastel.
Your
choice of paint
Choose
whatever paint suits you. Try them out and you will soon
discover whether you enjoy working with it and the results you
get or not. If you like certain properties of different paints,
you can try working with a mixture of paints (known as mixed
media) in one painting. The variation is both challenging and
rewarding.
The
advice and information above is meant as guidance to the
properties of the different paints. The only way you will know
if you like a particular paint is to try it.
By:
Ian Antonio
|
Interior-Tip.com
