These paintings are made with 23k double gold leaf in a traditional manner of applying gold gilding. Twenty-three karat gold leaf is 95.8% gold and does not tarnish over time. Gold leaf is gold that has been hammered into very thin sheets, about 0.12 micron thickness although double gold is 20% thicker. Double gold covers better and is more durable. It is still fragile to touch, so it is sealed with varnish for protection.