Artists often talk about the colour value and what it means. Put simply the value of a colour is its lightness or darkness as affected by the light (or lack of light) shining directly on it. Instinctively we think we know how different a colour can look under different strength lighting but I often underestimate how completely different the same colour can look. Here’s a great little demo that takes a typical flesh colour that you might use to paint a portrait. The artist puts it on his palette knife and turns it under the overhead light in his studio, comparing it as he does to the pre-mixed shades of different value. Watching it I was surprised how dark (and how light) exactly the same colour can appear. Prepare to be amazed!