CSS px is an Angular Measurement

Post by bzbarsky » Tue, Mar 13, 2012, 1:32 PM UTC

jonah wrote: post #55

bzbarsky wrote: post #44

Earlier quoted context omitted.

High-resolution devices (that includes iPhone 4 and iPad 3, but also every single printer anyone's used in the last 5+ years) are exactly why the spec says what it says. The only other option was to not have a "px" unit in the spec at all. I mean, think about it. Say you have a 600dpi printer. Take a typical web page that sets its body element to be 1000px wide, because the person writing it was using a 96dpi display…

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…

Interesting. Do printers use halftone screens for pure black-and-white content as well?

Post by jonah » Tue, Mar 13, 2012, 9:12 PM UTC

bzbarsky wrote: post #61

jonah wrote: post #55

Earlier quoted context omitted.

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…

Interesting. Do printers use halftone screens for pure black-and-white content as well?

If it's pure crisp black like text, then no.

Sometimes pure black is printed incorrectly and looks "fuzzy" with dots around the edges - in that case it is rendered with a halftone screen.

Re: CSS px is an Angular Measurement

Re: CSS px is an Angular Measurement