1998.05.10 02:26 "Re: Choose between TIFFScanline and TIFFReadRGBAImage", by Helge Blischke

1998.05.10 10:35 "RE: LZW compression and predictor", by Gilles Vollant

I've added, after my TIFFSetField(tif, TIFFTAG_COMPRESSION, COMPRESSION_LZW) a TIFFSetField (tif, TIFFTAG_PREDICTOR, 2)

The result is good!

Some size of the same image in TIFF format with LZW:

A 8 bits image:
LibTiff without predictor = 2: 180 KB
LibTiff with predictor = 2: 134 KB
Photoshop 4: 100 KB
Paint shop pro 5: 82 KB

A 24 bits image:
LibTiff without predictor = 2: 469 KB
LibTiff with predictor = 2: 225 KB
Photoshop 4: 229 KB
Paint shop pro 5: 198 KB

The 8 bits same image in GIF with Photoshop: 44 KB
The 8 bits same image in GIF with PSP: 44 KB
The 8 bits same image in PNG with Photoshop: 53 KB
The 8 bits same image in PNG with PSP: 40 KB

The 24 bits same image in PNG with Photoshop: 86 KB
The 24 bits same image in PNG with PSP: 59 KB