FAQ #3: Why is my snow grey?

Although this one has been oft-described in camera manuals and photo 'how-to' books galore, I wanted to cover the subject in a bit of detail, as it can be helpful to understand just a little bit about how your camera's meter works.

[I'll hit on an additional aspect of this in a week or so, e.g. how your software's histogram relates, and why you might not want to allow automatic contrast adjustments of certain images during post processing.]

Now, for the quiz part; the following picture is of a mono-colored piece of paper. The camera is a Canon S90 set to "P" (Program mode); any of my (or your) cameras would have given the same result. What color is it?

I'll be back tomorrow to answer the question...