After experimenting with pointillism early in her career, Bridget Riley turned to color field painting but became more interested in the optical effects created between forms, or what she calls “bleeps,” than in the relationship of figure to ground. Riley discovered that she could produce “bleeps” by using distorted geometric shapes. The repeated forms and lines produce illusions that draw the viewer’s attention to the processes of perception and evoke psychological and emotional responses. Although op and pop art are distinctive movements, their practitioners share a fascination with the processes of perception, and Richard Hamilton and Eduardo Paolozzi often incorporated references to op art in their work of the 1950s and 1960s. Riley creates her paintings through a long and painstaking process of experimentation, arranging and rearranging colored paper templates, and making detailed studies, such as Red and Blue, from which her studio assistants make the final works. Gallery label for installation of YCBA collection, 2016