Linolenic Acid content is what gives Linseed Oil its yellow tint, but it’s also what gives Linseed Oil its drying properties. Safflower Oil has almost no Linolenic Acid, so it dries slower and creates a softer, weaker paint film than Linseed Oil. If you like the color clarity of Safflower Oil but want a stable painting that dries properly, only use in the top layer.
Related video - Rublev Drying Oils:
youtube.com/live/tr9G_Csiqgk?si=u1axLzyfvlAijtia
Further reading:
justpaint.org/williamsburgs-new-safflower-colors/