Steve O
by the amount of carbon-14 that is in the organic compounds used in making the object the organic compound were plant & animal material such as fibers, fats & oils from something living the amount of C-14 present decreases by 50% in about every 5770 years the paint used may be a mineral base, but often they used a plant or an animal oil to mix with it fibers fron the canvas or paint brush also would have C-14 see "radiocarbon dating" @