The complete illustrated catalogue is available in two versions, as a printed book and as a package of CD-ROM and book combined. The CD-ROM contains the complete text of the catalogue with high resolution illustrations of every work owned by the National Gallery and on permanent or long-term loan. The indexes and search facilities on disc provide art historians, picture researchers and the interested general public with in-depth access to one of the world's most important collections of European painting from the 13th to the 20th century. In addition to the descriptions of works and biographies of artists, each work has an associated set of key words relating to general subjects (eg children, angels, winter), specific subjects (eg Samson, Mary Magdalen), and picture types (eg portrait, landscape, still life, altarpiece). The artist index includes aliases and alternative alphabetizations (eg Van Gogh under v and g). The material is organized alphabetically by artist as in the book. In addition to a comprehensive bibliography of major studies of the collection, a bibliography (as a pop-up) is available for each painting. The illustrations are available in two sizes: a "thumbnail" - approximately the same size on screen as on the pages of the book - and a much larger blow-up for closer study. The blow-up images have a maximum dimension of 1500 x 1500 pixels - equivalent to a screen area of 20" by 20", enabling users to study every work in the Gallery's collection in greater detail than in other printed or electronic versions. As in the book, all but 300 of a total of more than 2200 illustrations are in colour. Users have facilities for downloading and printing small-scale images and text for personal use (with copyright notices).