> Actually, for every type of picture, there's an upper limit beyond > which extra resolution is wasted. If you're interested in the > inscription, etc, you don't need to be able to focus on every > chrystal in the rock. I have found 300 dpi on an A4 picture is > easily enough - although I've done some at 600. What's more > > "Lesley Robertson" <[email protected]> DPI (actually PPI) is a print-specific attribute which on its own doesn't say anything about the resolution of the source. A P&S camera has a sensor maybe a quarter of an inch across... At 300DPI on the sensor that would be a picture of 75 pixels <G> Also: 300PPI is considered photo-grade for printing, 600PPI is throwing a lot of information at the printer that it can't use. On a pure CMYK inkjet printer, 300PPI data implies 150LPI (halftone line screen is commonly half the image pixel rate). For 256 grey levels one needs a 16x16 printer dot, so 150LPIx16 => printer DPI of 2400. Modern photo printers with half-intense pigments/dyes or special (true red/blue) allow for photo-grade printing using 1200 printer DPI (from the same 300PPI image size). Many subjects can be printed down to about 200PPI without noticeable degradation. What are the dimensions of an A4 page? A 4x6" print at 300PPI is 1200x1800 => 2MP camera. An 8x10" print is 2400x3000 => 7MP camera. Downgrading to 200PPI, those cameras can produce 6x9" and 12x15" -- bieber.genealogy Dennis Lee Bieber HTTP://home.earthlink.net/~bieber.genealogy/ Dennis Lee Bieber <[email protected]>