Morrie Gasser wrote: [re the difference between scanning at 300 dpi on a 600 dpi scanner, and scanning at 600 dpi and then downsampling to 300dpi in Photoshop] > Now, this implies that if Photoshop were simply to throw out every other > pixel of the 600 dpi image, rather than averaging, this should be identical > to scanning at lower resolution. Is this true, and if not, why? The unaccounted-for variable is the scanner software. If the scanner software does what you describe when scanning at an integral fraction of maximum resolution, then the result should be equivalent to resizing in Photoshop with the "nearest neighbor" preference set. In other words, you will drop out very small details entirely, and diagonal lines will look stairstepped. The alternative (using Photoshop's default of bicubic interpolation) is, as you suggest, some unsharpness. Resizing should generally be followed by a bit of unsharp masking or increasing the amount of unsharp masking you were already planning to do. However, there's no guarantee that the scanner software does what you suggest, and it certainly can't do just this if it supports scanning at non-integral fractions of its optical resolution. Asking for 400 dpi from a 600 dpi scanner means that the scanner is running at 600 dpi and the scanner driver is downsampling to 400 dpi (because the stepper motors in the machine can't move 3/2 of a step). It may be using a nearest neighbor algorithm, or it might be using bilinear, or bicubic, or some other downsampling algorithm, and it might be applying some sharpening as it goes. Only the driver writer knows for sure; if you're lucky and picky, the info might be in the manual. Botttom line: there's nothing that the scanner can do that will give you better results than scanning at max optical resolution and then downsampling and sharpening in Photoshop (or downsampling with "nearest neighbor" if you prefer sharp, jagged edges). The scanner software *may* do as well (especially for noncritical applications), or it may do much worse. Check out the difference and then do whatever gives the best quality / convenience tradeoff with your equipment. Russell Williams -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Please do your part: Stay on topic. Trim quoted messages. http://www.leben.com/lists for instructions on using this list.