This fifteenth-century drawing by Giovanni Bellini is one of the earliest drawings on blue paper in the Royal Collection. If you look closely at the bottom and left edges, you can see the original colour of the paper. This area was once covered by a frame or mount, whilst the rest of the drawing was exposed to light. 

When displaying works of art, light levels, temperature and humidity must be controlled in order to prevent the deterioration of the paper support and media. Paper conservators and collections care experts monitor environmental conditions to ensure they remain at safe levels.