Value is "the relative degree of lightness or darkness of a particular color." White is pure lightness and black is pure darkness. Intensity is the strength and vividness of a color. To change the intensity and value of other colors you must add black and white. Therefore, black and white are only tools used to modify other colors.
I think they adopted Corinthian order, for this type of orders can be seen on many cathedrals around Europe including those in France, Malta (Valletta), etc.
