lpi

Definition: lines per inch: measure of resolution or fineness of photo-mechanical reproduction. * Defines the half-tone screen ruling used to create a printing plate, hence sets the upper limit on fineness of detail that can be printed. * Normal magazine printing uses screen rulings of 133 lpi to 150 lpi, up to 180 lpi for very high quality. 300 lpi may be used for top-notch art reproduction onto top quality paper stock.
Forget Nyquist, just double up
As a general, easy-to-remember rule for doing those tricky resolution sums, assume a screen ruling of 150 lpi. With an over-generous quality factor of 2X to make things simple, you will want a file size that can deliver 300 dpi over the final image area. This gives a rather bigger file than is required. If that's too big, try using a screen ruling of 133 lpi with quality factor of 1.5X, to give an output dpi of about 200. You may find this gives pretty indistinguishably as good results

Related Terms: resolution

Previous Term: low-pass filter  Next Term: lumen