Edmund Industrial Optics Inc. has introduced fluorescent USAF 1951 resolution targets for calibrating the optics of fluorescence and confocal microscopes of UV-based imaging systems, and of instruments for photolithography and nanotechnology. The targets, constructed of fused silica and reflective chrome, are available in positive and negative patterns. The positive target has a chrome pattern over a clear background with fluorescent material on the front surface. The negative target has a clear pattern with a chrome background and fluorescent material on the back. The materials have peak absorption and emission wavelengths of 365 and 550 nm, respectively, and fluoresce in the visible when the target is illuminated by UV radiation.