Excerpt from Makoto Fujimura's article "Splendor", 2004:

In Kayama-sensei's memoir Infinite Space, he writes this about silver and gold, which he calls "the third color":

To me, gold and silver is the most mysterious of all the materials. Initially, I could not see the use of gold and silver in my works... I considered it, foolishly enough, pre-modern and inappropriate for our present time... So you might say, my view of gold and silver has changed drastically. Today, as I use considerable amount of gold, having mastered the material, I believe that such uses of traditional materials redefined my view of Nihonga*.

When he gathered us students to teach us how to use gold, he had one of his assistants bring a clear piece of glass. He then proceeded to glue the gold right onto the glass. Lifting the glass, he showed us that the most pure gold is nearly transparent as it casts a bluish light and halo. I mentally pictured the New Jerusalem "coming down out of heaven from God, prepared as a bride beautifully dressed for her husband" (Revelation 21:2). The transparency of gold that Kayama-sensei was displaying overlapped with John's vision. For the New Jerusalem is a "city of pure gold, as pure as glass" (Revelation 21:18).

*Nihonga are paintings that have been made in accordance with traditional Japanese artistic conventions, techniques and materials.