This signed screen print by Bridget Riley was released in 1978 in an edition of 75.
Untitled (blue) features lines rippling vertically down the canvas in hues that change at alternating lengths. Despite using just three colours, they merge and bounce off each other, creating a rainbow of varying hues. Each colour choice persists for one and a half wave lengths before merging into a new colour. Whilst viewing Untitled (blue) from a distance, the different shades are perfectly separate and recognisable. Yet, from a distance, they overlap and fuse together. This impression, combined with the evocation of movement within the lines, create mesmerising optical effects, from which the term Op Art takes its name.
The individual components of the canvas are not registered by the viewer. Instead, the work is viewed as a whole ‘field’ in which the resulting visual effect is created by an awareness of all the varying parts of the painting at the same time.