The Photo Quality option enables or disables the dithering of the PDF driver. When Photo Quality is enabled, seven high quality filters become accessible. Digital half-toning, also referred to as spatial dithering, produces the illusion of continuous-tone pictures on media that is only capable of displaying binary picture elements, for example, fax machines and most printers. Floyd-Steinberg, Jarvis-Judice-Ninke and Ordered Clustered are the text book filters. The Smooth, Sharp, and Stucki filters are less known, but produce better quality output. Floyd-Steinberg is the default setting. The sample view shows the selected settings on a test image. Threshold filter compared each pixel value against a fixed threshold. This is the simplest dithering algorithm, but it can drastically reduce file size due to the loss of detail.
Intensity
The photo quality program group also contains a scroll bar that lets the user control the intensity of the output image. The lower the intensity value is, the darker the output image changes.
When to Use Photo Quality Output?
· Photo Quality Output is designed primarily for faxing or to transmit color pictures on a monochrome device. When a color picture is faxed from a conventional desktop fax machine, the result is unrecognizable in most cases. On computer-generated faxes, the output quality can be increased to picture quality using the Black Ice printer driver. Since the Photo Quality options are designed for monochrome output, Photo Quality options are not available when the selected output color depth is 24bit.
· How is performance affected by the Photo Quality output?
The fastest filter is the Floyd-Steinberg, because it requires the least computation. Stucki is the slowest filter but has the highest quality and produces the best visible output.