|Pure Gum Turpentine Resin|
Mastic Varnish has a semi-gloss finish that naturally increases color luminosity. It is an extremely durable varnish and is often used in conservation and restoration work. Being one of the strongest binding resins, mastic is quite permanent. The addition of natural mastic resin to turpentine as a varnish dates back to at least 700 B.C. At the time of the Old Masters, it became common as a finishing varnish as well as a major ingredient in oil painting mediums. It continues to protect master paintings in museums around the world.
This natural resin is a chewy, light-colored, sap-like substance which grows on the Pistacia Lentiscus tree (an evergreen related to the pistachio tree). It can be found growing almost exclusively on the island of Chios, off the coast of Greece. The word "masticate" (to chew) comes directly from the Greek word for this resin (masticha), as it was first used in chewing gum and other Greek candies.
Make sure your painting is dry to the touch, and no areas are still wet as the paint might run. Paintings can be varnished within 2-3 weeks after completing the painting, but if you wait longer it is recommended you wait 6 months.
Use a soft, natural bristle brush (Flat, preferably 1.5 or 2 inches).
Dip the brush into the jar of varnish, and press against the rim to remove excess varnish. Brush the varnish onto the painting, spreading the varnish as you go to create a thin layer. Do not scrub very hard, just enough to spread the varnish around. The varnish will start to set up and get tacky quickly, so don't go over areas many times. When necessary, dip brush into jar again and continue brushing onto painting until fully covered with an even thin layer.
Paintings usually require anywhere between 1-3 coats. Make sure varnish is again dry to the touch and not tacky before applying another coat. Leaving a painting in the sun will usually dry the varnish in 1 day. Depending on climate, you may have to wait a few days to apply another coat.