Kind of a simplistic question, but my curiosity cannot be assuaged. When you look at pure cocoa powder, it has a light brown color, like a milk chocolate bar. And yet a dark chocolate bar, which is much higher chocolate content than milk chocolate, is a vastly darker color than cocoa powder. Even a 100% pure cocoa chocolate bar is a very dark color.
Pure cocoa powder
Milk chocolate bar
Dark chocolate bar ~75% cocoa
Dark chocolate bar 100% cocoa
What is at work here? I know chocolate has fats and solids other than cocoa in it, but that just makes it more confusing why a pure chocolate bar is dark as well. Does compacting the cocoa into a solid form (which is how I assume you make a pure cocoa bar) darken it that much? Are there differences in preparing the cacao beans (like different roasts for coffee)?