What is one foot-candle?

I've been thinking of luminosity and luminance in painting a lot this week. What does color and paint do to create an illusion of light emanating from a painting, and what is a measure of light?

My question "what is one foot-candle?" came up after a few days, as I recalled details from my first deep dive into color and light years ago.

I answer those questions here, in the video, and show you beautiful, powerful artworks that clearly embody luminance, glow, and shimmer.