Barrier-grid animation or picket-fence animation is an animation effect created by moving a striped transparent overlay across an interlaced image. The barrier-grid technique originated in the late 1890s, overlapping with the development of parallax stereography (Relièphographie) for 3D autostereograms. The technique has also been used for color-changing pictures, but to a much lesser extent.
The development of barrier-grid technologies can also be regarded as a step towards lenticular printing, although the technique has remained after the invention of lenticular technologies as a relatively cheap and simple way to produce animated images in print.