This program is part of Netpbm.
pgmbentley reads a PGM image as input and performs the Bentley Effect,
and writes a PGM image as output.
The Bentley Effect is described in 'Beyond Photography' by Holzmann,
chapter 4, photo 4. It's a vertical smearing based on brightness.
pgmoil, ppmrelief, pgm
Copyright (C) 1990 by Wilson Bent (firstname.lastname@example.org)
netpbm documentation 11 January 1991 Pgmbentley User Manual(0)