Oil Absorption
A measure referring to the amount of oil which is absorbed by pigments under standard test conditions.
Oil Bound (Water Paint)
Water paints which have a percentage of drying oil incorporated in the binder.
Oleo-resinous
Varnishes, binders, mediums, vehicles. Composed of drying oil and natural or synthetic resins.
Opacity
The hiding power of a coat of paint to obliterate the colour of the surface being painted, (see Obliteration).
Opaque Finish
A paint that is described as opaque will give a solid colour and finish.
Blacks and whites are always opaque and any colour mixed with them will become more opaque.
An Opaque coating/finish if applied to glass will obliterate any light shining through.
