Combing linseed oil (properly prepared) and colophony using turpentine at room temperature makes a mixture. The physical and chemical properties of the materials remain the same.
Combining linseed oil (properly prepared) and colophony (with or without turpentine) at temperature that exceeds 150C creates a compound(varnish)which has properties (film forming, increased surface protection , higher index of refraction) than any of the original components.
on we go ,
Joe