The Pointillists experimented with optical colour mixing to create intense glowing fields of light. Pupils can produce landscapes in which small brushstrokes of primary colours placed next to each other will create secondary colours when viewed from a distance; eg red and yellow will merge to form orange as the eye mixes the colours (see "The Side Show" by Seurat). Pupils can use a magnifying glass on a colour photograph to reveal how coloured dots are laid down similarly to create complex fields of subtle colour, leading to a study of Lichtenstein's use of coloured dots in his paintings.
Assemble a large still life in a corner of the art room. Use boxes, bottles and other objects of simple shape, painted with white emulsion. Borrow a prism from the science department to break a beam of light into coloured rays. Project these onto the still life - they will bend and change in tone as they follow the contours of the objects. Pupils must observe this closely and reproduce the still life, concentrating on mixing the tones of colour to extend their artistic vocabulary.