The accurate measurement of color in a product is a very difficult matter and is usually attempted in considerably simplified form in the food industries, as for example, by canners in standardizing and in improving the color of tomato products. It is much simpler to state that a certain tomato paste has, let us say, 0.01% lycopene—the principal coloring matter of the tomato fruit—than to measure the color, which means, in effect, describing its redness in quantitative terms.