Two seperate measurements can be taken from the output - lpi and dpi.

LINES PER INCH

The term Lines per inch - lpi is measured down the length of the page or positive as it refers to the number or frequency of these printed lines per inch, down the page. The higher the lpi the finer and more detailed the positive become. Lpi is also known as the screen ruling or screen frequency of a halftone screen.

Deciding on the correct lpi depends on various factors, of which a few would be; the Colour Separation method used for the design, the inks system, correct mesh selection and your printing capabilities and setup.

The term Dots per inch - dpi is measured across the width of the page or positive as it indicates how many dots of ink or toner, per linear inch the printer can print. This is the output printer's resolution, typically Laser Printer's have a resolution of 300 to 600dpi and Imagesetters start at 1200dpi.

The dpi of the output printer will effect the density or "blackness" and the sharpness of the final positive, in other words the more dots of ink or toner the output printer is able to print the better the end result will be.