actually, we call it a footcandle meter because it takes readings in footcandles. 363 days of the year you can come here and see matisse's cutouts, but you can only see them for 4 hours per day, not 7 or not 8. that means that we have effectively reduced the exposure time by about half. that's good for the cutouts, and it's good for the public. richard: at the national gallery of art, we have many sculptures: some made of wood, some of metal, some of stone. most of these works are exhibited inside the buildings. there are also sculptures that are exhibited outdoors. these works are exposed to the elements--rain, snow, pollution, bird droppings. it is the object conservator's job to care for all of these sculptures. woman: i want you to take a look at this wonderful sculpture-- probably one of the most famous from the 19th century. it's called the shaw memorial. it's by augustus saint-gaudens. this is a memorial to robert gould shaw-- who's the captain right here on the horse-- and the 54th massachusetts volunteer regiment during the civil war. anybody know what this might be made of? w