Rob Miracle <rwm@photo-miracles.com> writes: > At 01:05 PM 10/15/2002 -0500, you wrote: > >I've seen sufficiently many reports of people seeing improvements in > >Epson inkjet output at ppi values up to 720 that I don't consider 240 > >to be optimum. It's more like "minimum professional level" or > >something -- despite the fact that I've passed off 150 ppi Epson > >prints to professionals on occasion (it all depends on the subject, as > >usual). > > If you print 720 dpi, you will only get 1 pixel vertically since most > of these printers only print 720 dpi vertically. So each pixel will > be represented by a grid thats 2 x 1 on a 1270, or 4 x 1 dot grid for > the 1280 (2880 x 720). For the Epson 2200, at 2800 x 1440, your dot > grid is 4 x 2. It can't lay down enough color combinations to dither > the apparent continuous tones needed to make it look like a photo. > What most likely happens is that if you print a 720 DPI image to the > Epson print driver, it probably resamples the image so that it will > have enough ink dots per inch to print each pixel. I'm sure the driver doesn't use the ppi of the image I send for anything at all. But I think it looks at the amount of data it has, and uses the data in complex ways, and I don't find it unbelievable that people see marginal improvements with additional data above 240 ppi. The driver is *already* doing very complex playing with the image -- mapping a pixel to a fixed region on the paper is *not* what goes on in Epson drivers. -- David Dyer-Bennet, dd-b@dd-b.net / http://www.dd-b.net/dd-b/ John Dyer-Bennet 1915-2002 Memorial Site http://john.dyer-bennet.net Dragaera mailing lists, see http://dragaera.info
