Re:CSS px is an Angular Measurement
by jonah on Tuesday March 13, 2012 @03:59AM
(#3697447)
Confusion between px and dpi are common for people who haven't done work for both screen and print:
Screens are more accurately measured in PPI (pixels per inch) while the smallest elements a printer can produce (more akin to each of the 8 bit sub-pixels on a screen) are measured in DPI (dots per inch). Since ink is 1 bit more smaller elements (dots) are needed in some sort of dithered pattern to represent grays and colors.
Using halftone screening [1] the image elements are called lines and so a 600dpi printer is capable of producing 85–105 LPI (lines per inch)[2].
The lines per inch of print are more analogous to the pixels per inch of a screen than dots per inch are.
So, that 96ppi LCD and the 600dpi printer have around the same information density for practical purposes.
Screens are more accurately measured in PPI (pixels per inch) while the smallest elements a printer can produce (more akin to each of the 8 bit sub-pixels on a screen) are measured in DPI (dots per inch). Since ink is 1 bit more smaller elements (dots) are needed in some sort of dithered pattern to represent grays and colors.
Using halftone screening [1] the image elements are called lines and so a 600dpi printer is capable of producing 85–105 LPI (lines per inch)[2].
The lines per inch of print are more analogous to the pixels per inch of a screen than dots per inch are.
So, that 96ppi LCD and the 600dpi printer have around the same information density for practical purposes.
[1] http://en.wikipedia.org/wiki/Halftone [2] http://en.wikipedia.org/wiki/Halftone#Resolution_of_halftone...