Looker

Described as an image processing program, it is primarily concerned with the conversion of colour images to monochrome or greys by use of dithering and half-toning, both of which allow extensive user control over their parameters. You can lighten or darken a picture, negate it or access the colour values to alter the converted image. Looker loads PI1, PI3 and DTH formats and saves as PI3 and DTH. Looker is well documented but entirely command driven, therefore not really user friendly.