# ppmdither

Ppmdither User **Manual(0)** Ppmdither User **Manual(0)**

## NAME

ppmdither - ordered dither for color images

## SYNOPSIS

**ppmdither**
[**-dim** *power*]
[**-red** *shades*]
[**-green** *shades*]
[**-blue** *shades*]
[*ppmfile*]

## DESCRIPTION

This program is part of **Netpbm(1)**.
**ppmdither** reads a PPM image as input, and applies dithering to it to
reduce the number of colors used down to the specified number of shades
for each primary. The default number of shades is red=5, green=9,
blue=5, for a total of 225 colors. To convert the image to a binary
rgb format suitable for color printers, use -red 2 -green 2 -blue 2.

## OPTIONS

**-dim** *power*
The size of the dithering matrix. The dithering matrix is a
square whose dimension is a power of 2. *power* is that power of
2. The default is 4, for a 16 by 16 matrix.
**-red** *shades*
The number of red shades to be used, including black; minimum of
2.
**-green** *shades*
The number of green shades to be used, including black; minimum
of 2.
**-blue** *shades*
The number of blue shades to be used, including black; minimum
of 2.

## SEE ALSO

**pnmdepth(1)**, **pnmquant(1)**, **ppm(1)**

## AUTHOR

Copyright (C) 1991 by Christos Zoulas.
netpbm documentation 14 July 1991 Ppmdither User **Manual(0)**

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