Linseed oil is extracted under high pressure from linseed, then clarified naturally by exposure to sunlight.
Linseed oil features the highest degree of siccativity and durability of all paiting oils.
However, it has a strong tendency to yellow when it dries.
For this reason, it is particularly used for grinding the deepest colours in the palette, or those with least siccative qualities (e.g. ivory black).