Normally we strive to produce the sharpest images possible. However, one common exception occurs when printing portraits. Most subjects don't appreciate having lines, wrinkles, and skin blemishes revealed in sharp detail. Portrait Diffusion Grids have been used for decades to soften and minimize the appearance of those unwanted facial details. Unlike diffusion filters which simply blur the image, projecting the image through the steel mesh grid uses diffraction to reduce resolution. The effect can be controlled by changing the lens aperture, adjusting the distance between lens and grid, or making only part of the exposure with the grid.
The #429-015 Portrait Diffusion Grid can be installed directly on Omega B600 and C700 enlargers in place of the red safety filter, and it also can be placed in any of the Omega under lens filter holders.