“银幕（silver screen）”中为什么用“银（silver）”？

“银幕（silver screen）”中为什么用“银（silver）”？

A silver screen, also known as a silver lenticular screen, is a type of projection screen that was popular in the early years of the motion picture industry, and is still used in projecting 3-D films.

The term silver screen originated in reference to the actual silver content embedded in the material that made up the screen's highly reflective surface. While actual silver screens are no longer commonly used, the term silver screen has passed into popular usage as a metonymy for Hollywood and the movies.

就是说幕布上面涂有一层反光的物质，里面含有银。