Online display will never do you any good and in fact mess up size if you shoot for more than 72ppi. In truth the dpi means nothing for onscreen... What counts is the xy pixel size. 72 ppi will only actually measure out to 72 pixels in a single physical inch on a 14 inch monitor at 800 by 600 pixel resolution. (800/72 is just over 11, 600/72 is just under 8.5, 118.5 inches is the size of a 14 inch monitor). For print you want a resolution in 'ppi' that is equal to the 'line screen (lines per inch)' of the printer times 1.5 lpi for even the best professional printers is rarely above 150 (2400 dpi (printer dots per inch) printer). Newspapers print in the 70's somewhere. This is assuming color with 256 tone levels per color. Which means a single 'halftone dot' will be a 16*16 square of printer dots at full strength of that color. Which is the level at which you will see professional printing. Home inkjet printers obviously don't have resolutions of 2400 dpi color. So they trick it. They sacrifice line screen to get good tone value and use a variety of guessing algorythms to make it seem better than it truely is. In the end your home printer will have a linescreen equalvalent to somewhere between 70 and 100 lpi as far as what you'd use to determine quality of the images you send to it. For a proffessional printer ask them their lpi. Paper quality affects this also. But anyway... That's printers. Once you know your printer's lpi multiply it by 1.5 (some say 2.0, 1.41 is the minimum) and that will give you the ppi (pixels per inch) resolution you'll want. Above that you won't notice the added resolution giving any benifits to the printing. Below it and you just might.

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