This report describes image processing techniques which could be used to improve the perceived resolution of archive video recordings. It has been found that the benefits obtained using linear methods are limited. However, a non-linear method is described which can be used to sharpen edges. The technique has been used successfully to enhance images with a significantly smaller visible increase in ringing and noise than for a comparable linear method. It has been developed as a tool for archival retrieval in conjunction with other techniques such as noise reduction, unsteadiness correction, and advanced PAL decoding.