2008.11.21 20:18 "[Tiff] Patch Legacy App for Updated libtiff?", by Kevin Myers

2008.11.22 16:26 "Re: [Tiff] Re: LZW compression in your legacy app", by Kevin Myers

Dithering will affect compressibility. Obviously compression would be much greater if simple quantisation to the new palette is done, rather than error diffusion, but I am sure you know that. You could also try ordered dither.

Because dithering generally has an adverse effect on image compressibility, and because none of these documents had any true color gradients to start with (not counting printing, reproduction, and scanning artifacts), and because I want to approach the original "pure" colors in the documents as closely as possible, I have avoided the use of dithering when processing these images. However, I appreciate your comment regarding possible use of ordered dithering, since that would improve compressibility using LZW compared to other dithering options such as error diffusion.