||1. Aqueous: distemper, casein. Egg tempera does
change the colour slightly over the years.
2. Fir balsam resin: (Strasbourg turpentine fused
with pure spirits of turpentine). A few eye-drops
of walnut oil are added for a tough paint film.
3. All oils alone should be avoided since this will
lead to discoloration even after the pigment is
prepared. The best was achieved with linseed stand
oil and pure distilled turpentine. Even cold pressed
walnut oil will show discoloration within three to
four years. However, a small addition of any white
pigment when oil is used will prevent noticeable