The keywords are held in 5 levels. To do a search first select a heading from the Level-1 keyword list e.g. Object Type. Then from the level-2 keyword list select Paintings. Then from the level-3 keyword list select Watercolurs. Then click on the search button to see all images on that subject. After selecting your subject you may also select a time period by using the "Select a date" box and then selecting from the drop down list.