We are doing Creative works so we need to know some basic. For Pre-press works. LPI, DPI, You think it is impotent?

I think we should speak about PPI , LPI and DPI

PPI = Pixels Per InchLPI = Lines Per Inch

DPI = Dots Per Inch

three of them have a different usage, while PPI use to measure the Qulity or resolution of images in the received file from customer and we should know that resolution between200 -300 DPI are recommended for Press printing , DPI use to measure the Qulity or resolution of the objects in the artwork and we should know that resolution between 2000 to2400 are recommended for Press printing, LPI use to measure the Qulity or resolution of outputs (films or Plate) and this reflect the quality of final printing output and we should know that resolution deffer form WEB to Sheet printing methods within range of130 -150 lpi . 

All  that also deffer with the quality of paper and inks used for printing, so the High quality of paper and ink will reflect the quality of LPI value.