Problems in the use of selective optical spatial filtering to obtain enhanced information from electron micrographs

SUMMARY Possible hazards in the use of optical spatial filtering applied to the analysis of electron micrographs are illustrated. Two experiments show how information is either lost or spuriously introduced into reconstructed images of micrographs when (a) only one part of a two‐part micrograph image is reconstructed and (b) when noise is eliminated from the reconstruction.