Art Spectrum 100mL Refined Linseed Oil Small amounts of Art Spectrum Refined Linseed Oil added to oil paint will enhance flow and slow drying. This is particularly useful for 'alla prima' techniques (where the artist quickly paints wet on wet, with paint straight from the tube). Art Spectrum Refined Linseed Oil is also used in making mediums. Art Spectrum Refined Linseed Oil can also be used to clean brushes.