At Sun, 30 Mar 2003 14:30:38 +1000, Adam W wrote: > > > Ps2pdf is cool, but it would be even nicer to have ps2tiff, as > > > windows users don't need the pdf reader (which most ppl have > > > anyway), they can just use the inbuilt kodak image program. > > > > I presume you're aware that ps/pdf is a vector format and tiff is > > a raster format, and are aware of the implications that has on > > image size, quality, etc.
postscript (and pdf) is a "vector" format, meaning it contains instructions for drawing using primitives like lines, coordinates, areas, etc. tiff (and gif, png, jpeg) is a "raster" or "bitmap" format, meaning it contains a big array of pixels (colour values) - one for each "dot" that will appear on your screen later. a postscript may contain a bitmap image as one of its drawing "instructions" - but the extra ps/pdf overhead makes it not as efficient a storage format. for line-art or text or such things, a vector format is usually a much better choice, since storing the primitives at such a high level is more space efficient and allows later conversion to bitmaps at varying resolutions without information loss (screen vs printer is quite a bit resolution difference). for photos, faxes or scanned images, these come in as a bitmap and are most suitably stored as a bitmap. the image in typical photographs (in particular) is way too complex to be accurately or efficiently reduced to vector primitives. so, the general rule of thumb is: if its a raster image, keep it that way. if its a vector image, keep it that way until as late as possible (assuming you have a raster display device as the last step). ie: be wary of converting from vector -> bitmap. > Maybe we're talking different tiff formats... See in our office we have > one of these panasonic DigiFax, which scans and emails you a tif of the > "fax". You open it in this kodak program(or really any image viewer), > and it supports multiple pages within the one tif file. If these images are scanned, they will be a raster format already and thus any of the numerous raster file formats are appropriate. I would probably choose PNG or TIFF, depending on whats available on your users' computers. although it will work, postscript (or any other vector format that may include bitmaps) is not the most space efficient way of storing such information. In particular, if its a fax (or scanned into the fax format), then its in "g3" format, which is a fairly coarse bitmap. note that tiff isn't really an image format, its more of a "container". the tiff header merely says what format the rest of the file is in. this means that its cheap to add/remove a tiff header to (eg) a g3 image, but it also means that you'll have to check target programs for specific tiff subformats - merely saying "i support tiff" is insufficient to cope with every possibly tiff image. -- - Gus -- SLUG - Sydney Linux User's Group - http://slug.org.au/ More Info: http://lists.slug.org.au/listinfo/slug
