Hi, I've tried to google, but I can't answer this specific question. I suspect the answer is in the filtering, but I can't find one that works for me. If anybody knows the answer I'd appreciate a point in the right direction.
I have a 4-bit (16 color) greyscale tiff that's 3755390 bytes. Photoshop's 'save for web' conversion to gif saves it as a 16-color non-interlaced LZW gif of size 226014 bytes with the original dimensions. There are indeed 16 colors, but it's done some kind of sharpening/dithering, which I would have expected to decrease the compressibility. The Histogram and the mean have changed slightly. I can't get Imagemagick to create a gif smaller than 392366 bytes, significantly bigger. I've tried -strip, -filter Lanczos, -unsharp, -sampling-factor, - everything I could find but I can't get smaller. What am I missing? The only thing I can think that Photoshop is doing is prefiltering intelligently to increase the redundancy so that it LZW compresses better. Is there any way of doing that in Imagemagick? I can post the 3 images somewhere if that would help. -- Illtud Daniel [EMAIL PROTECTED] Uwch Ddadansoddwr Systemau Senior Systems Analyst Llyfrgell Genedlaethol Cymru National Library of Wales Yn siarad drosof fy hun, nid LlGC - Speaking personally, not for NLW _______________________________________________ Magick-users mailing list [email protected] http://studio.imagemagick.org/mailman/listinfo/magick-users
