The difference between different types of paint is an important one. Many of the visual aspects of a painting are dependent upon the particular type of paint that was used in its manufacture.
What is paint? Well… it’s nothing special. People regularly make their own paints or adapt existing ones. The main constituents of paint are:
|Pigment||This constitutes the color element of the paint. Pigment is, in its pure form, usually a powder. Some are derived from modern chemical processes and others are derived from stuff you can dig up out of the ground. The paint itself is often named after the pigment. Hence: Ivory Black (which used to be made from burned irony), Cadmium Yellow (cadmium sulphide) and Titanium White (titanium oxide). Some pigments are cheaper than others, which explains why some paints are cheaper than others.|
|Binder||The binder is the glue that holds the pigment in place. In the case of oil paint this is usually linseed oil.|
|Extender||Pigments can be very expensive. An extender is, in essence, a blank pigment that is used to stretch the distance that the paint / binder can cover. You can’t go far wrong from envisioning the extender as a powdery chalk. Cheap paints have more extender and less pigment.|
Oil paint and acrylic
The two mediums that this course will explicitly support are oil paint and acrylic paint. However, in your final project you are free to use whatever medium you wish. Oil paint is an ancient medium (there is evidence of its use in the making of Indian wall painting two thousand years old) but it was its use European painting that saw its most sophisticated usage. It was the Dutch who pioneered its use in the west and also pioneered its application on canvas supports, as opposed to the plaster walls that had till then been the norm.
Oil paint may be applied over an oil-based primer or an acrylic primer. Acrylic paint is more recent, being a side product of the 1930s plastics industry. A painting made using oil paint can maintain a higher pigmentation load than one made from acrylic. A painting made with acrylic paint can have many of the qualities of one made with oil paint but it can dry a lot faster. this is either a good thing or a bad thing depending on your needs. It also has a subtle plastic sheen to its surface. The two mediums ‘feel’ very different to work with: a difference that is best left for you to discover.
A medium will dilute the paint to make it travel further across the painting surface, lay flatter upon the surface and perhaps dry quicker. In the case of oil paint the medium is usually linseed oil but can be such things as poppy seed oil, stand oil and damar varnish. In the case of acrylic, it is usually water, though it can be any of the many commercial mediums. There is a wide range of acrylic-friendly mediums to choose from: retarder a (to slow the paints drying time), sicative (to speed theaints drying time), gloss and matte mediums etc.
Painting in any medium requires that the brush be cleaned regularly. This cleaning is not only between changes of color but also when you wish to less or increase the amount of paint on your brush. This is referred to as loading or de-loading the brush and requires that you have a rag at hand and also a medium in which to dip your brush and swish it around. In the case of oils isn’t this is turpentine or brush cleaner. In the case of acrylic this is dihydrogen monoxide.