The RKD Iconography collection consists of around 150,000 images of paintings, drawings and prints. It is a supportive collection that is indexed using unique codes from the Iconclass system. This iconographic classification system is supportive in that it is used worldwide by museums and other heritage institutions for captioning and indexing images (art works, book illustrations, reproductions, photographs, etc.). You can conduct an online for specific subjects in Explore using the displayed Iconclass codes. Alongside the physical collection of images there is also an iconographic book collection which is categorised according to the Iconclass system.