Sub-50 nm lines, holes, and posts have been patterned photolithographically using near-field embedded-amplitude masks and an exposing wavelength of 220 nm generated by an arc-lamp source. Interference in the optical near field is utilized to produce the fine patterns. In some cases, the feature sizes on the mask are more than six times larger than the size of the smallest features patterned on the substrate. Numerical simulations support the experimental results. (C) 2002 American Institute of Physics.