Types of pigments
Organic pigments are composed of carbon compounds. Before they
were synthetically produced they were usually of animal
and vegetable origin. Examples of synthetic organic pigments
are: alizarin, azo-pigments (the yellow, orange and red colour
range), phthalocyanine (blue and green colour range) and
quinacridone (a lightfast red-violet pigment).
Inorganic pigments (of mineral origins) are metal compounds, for
example oxides. Compared to organic pigments they are few in
number. Examples of natural inorganic pigments are umbers, ochres
and siennas as these are excavated from the ground. Pigments with
the same names are also produced synthetically. Other examples of
synthetic inorganic pigments are the cadmium yellow/orange/red,
cobalt blue and titanium white.
Lake pigments are dyes that have been made insoluble for
certain liquid binders or thinners. This is done chemically by
precipitating the dye on (or fixing the dye in) a colourless
substance (inert pigment) that is indissolvable for the particular
binding agent. Although the lightfastness of the dye is
improved as a consequence, this is only to a small degree.
What's more, lake pigments have the bleeding property of dyes: the
colour penetrates other paint layers or spreads across the