| TIFFDITHER(1) | LibTIFF | TIFFDITHER(1) |
tiffdither - convert a greyscale TIFF image to bilevel using dithering
tiffdither [ options ] input.tif output.tif
tiffdither converts a single channel 8-bit greyscale image to a bilevel image using Floyd-Steinberg error propagation with thresholding.
| Compression | Description |
| none | no compression |
| packbits | PackBits compression |
| lzw | Lempel-Ziv & Welch compression |
| zip | Deflate compression |
| g3 | CCITT Group 3 (T.4) compression |
| g4 | for CCITT Group 4 (T.6) compression |
By default tiffdither will compress data according to the value of the Compression tag found in the source file.
The CCITT Group 3 and Group 4 compression algorithms can only be used with bilevel data.
Group 3 compression can be specified together with several T.4-specific options: 1d for 1-dimensional encoding, 2d for 2-dimensional encoding, and fill to force each encoded scanline to be zero-filled so that the terminating EOL code lies on a byte boundary. Group 3-specific options are specified by appending a :-separated list to the g3 option; e.g. -c g3:2d:fill to get 2D-encoded data with byte-aligned EOL codes.
LZW compression can be specified together with a predictor value. A predictor value of 2 causes each scanline of the output image to undergo horizontal differencing before it is encoded; a value of 1 forces each scanline to be encoded without differencing. LZW-specific options are specified by appending a :-separated list to the lzw option; e.g. -c lzw:2 for LZW compression with horizontal differencing.
The dither algorithm is taken from the tiffmedian program (written by Paul Heckbert).
pal2rgb (1), fax2tiff (1), tiffinfo (1), tiffcp (1), tiff2bw (3tiff)
LibTIFF contributors
1988-2023, LibTIFF contributors
| November 23, 2023 | 4.5 |