The objective of op art was to play tricks on the eye.
Op art was one of the most important new art forms to have emerged in the second half of the 20th century. Also called optical art, it was art that was created to be viewed not so much as a beautiful creation, but to confuse the viewer through optical illusion. Popular in the 1960s, and in all aspects of design, Bridget Riley and Victor Vasarely were two of its key figures.
Black and White
Used for many optical art effects, black and white made a powerful impact on the retina because of the color contrasts. These contrasts emphasized the optical effect of an artistic piece. Notably, black and white have a such an impact on the retina that the viewer struggles to differentiate between what part of the artwork is in the foreground and what is the background. Bridget Riley was one of the leading exponents of black and white in the op art movement.
Color
Artists experimented with color through op art. An example is showing how color looks darker when the background is light. Artists also discovered utilize one shade of a color; through manipulation of shapes, the retina would be confused into thinking that it was seeing more than one shade. The effect of different colors, when used in geometrical shapes, also had a dramatic effect on the viewer and made it difficult to determine exactly where an image began and ended. Victor Vasarely was a master of this technique.
Light
Light was exploited effectively in op art. Some op artists designed work that was meant to be looked at from various angles, which would display the ever-changing nature of light reflecting off the painting's surface, such as Getulio Alviani. Artists also recognized how the effect of luminosity could be achieved. This effect involved a gradual change in the brightness of colors being perceived by the retina, by the border of a painting. The blurring of shapes was also used in op art as an effect that would often dazzle the viewer.
Moir
Moir was one of the most popular of the styles used in op art. The effect was achieved by the overlapping of two lines, with often a blurred image being seen by the retina. Slight alterations would radically change the appearance of the moir pattern, and simple designs could be used to create very intricate patterns. Using curved lines was a very popular method of utilizing the moir effect at the height of the op art movement. The moir effect can now be achieved inadvertently on computer graphics software.
