The four drawings on display were all prepared in chalk on paper, a very different medium from oil or watercolour. Artists used chalk to make quick preliminary sketches but, increasingly from the late Renaissance, they employed it as a medium in its own right for finished drawings. Chalk was often favoured by draughtsmen because its texture enabled an artist to draw exact lines and portray light and shadow effects.
By the date of these drawings, several types of chalk were available to convey an expressive range of features. Black, white and red chalks were those most commonly used and they were manufactured through pulverising, washing and shaping to resemble charcoal pencils. Of the various tints employed, white chalks were used to achieve reflections of light as individual accents. However, as chalk did have a restricted palette it was unsuitable for colouring broad areas and drawings were sometimes coloured with pastel crayons. Successful portrait artists were extremely skilled in the use of chalk, as the drawings here on display show. Due to their vulnerability to light and temperature these drawings are rotated half-yearly to preserve their condition.