Perhaps I look at some things too deeply (and at others not enough :)...but the testing method can lead to false conclusions, when testing bitmap output at different resolutions at the same physical output size with given content on a given device. One must be careful of how one performs the test.
Ideally one would have a VECTOR file, sharp lineart and smooth gradations and more photorealistic renderings done in vector, approximating photography as much as possible with vectors (not easy, but not too hard - there are some excellent vector illustration artists out there and if you have vector software there are examples ore clipart etc). I guess a STN file from GF or a Mr SID file or some other fractal/vector/flavour of month method may do too (presuming enough good pixels in the original to encode into the 'pixel-less' state). Or even perhaps multiple scans with locked settings, apart from the resolution differences (no USM). My theory being that these 'sans-pixel' files are then rasterized at the test resolution, all at the same physical size (no USM). This will remove variables from the test, which can slip in when using more traditional raster/pixel/bitmap originals and resizing them. But if starting from an image at say 360 ppi at final size, then comparing 300 ppi or 260 or any other number to see what happens at output - will involve resampling down to the other resolutions at the same print size. This will soften the image, the more so with greater reductions of resolution. USM can bring back the appearance of snap - but how to evaluate and ensure that all the resized files at different resolutions all have the same snap without throwing off the test results (which are often subjective). This is not the same as the original data and may lead to less than scientific conclusions based on the amount of pixels discarded and how this plays with the image content at hand. Sharpening can also be hard to evaluate, the resampled images should have some USM, but how to be objective that all the different pixel dimensions and sharpening are the same and that this is not what makes the image look better, rather than the resolution. Hope I am making sense. Perhaps I am looking too deep at things or worried about nothing, but this is the sort of stuff I have done in the past to ensure 'objective' analysis of resolution and print output for a given image and output process. Digital photos and stochastic screening are a lot more forgiving than scanned film and halftone dots - one can get away with lower resolutions when compared to traditional methods. P.S. In years gone by, many average trade house scans to be drum scanned at Res12 (120 ppcm - a little more than 300 ppi) - but when doing cosmetic work, either product shots or female faces, Res 14 or 16 scans were often common, to help smooth out fine sharp lines and to 'oversample' and smoothout the skintones. This was a case of intentionally providing more data than what would be required for an 'average' image in the same conditions. This PDF is quite good - this is a complex issue: http://www.ledet.com/margulis/PP7_Ch15_Resolution.pdf Regards, Stephen Marsh. =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
