On Wednesday 27 October 2010 at 00:45, Paul Louden wrote: > On 10/26/2010 5:40 PM, Antony Stone wrote: > > I find this question hard to manage - isn't resolution a quantity, which > > is measured in units of DPI? > > > > How can screens of different DPI have the same resolution? > > DPI means "dots per inch." Resolution is an absolute measure of dots. A > 1280x720 16 foot projector has the same resolution as a 1280x720 9 inch > netbook. But the DPI of them is drastically different because while the > number of dots is the same, the physical area of the screen isn't.
I think you're confusing pixels with resolution. Pixel (or dot) density refers to the total number of dots on a device (no matter what size it is). Resolution is the number of pixels (or dots) in a given distance or area (usually inches). A printer with a resolution of 300dpi is a 300dpi printer, no matter whether it takes A6 paper or A0 paper. A display screen with a resolution of 75dpi is a 75dpi screen, no matter whether it's 1.5" across or 12" across. From http://en.wikipedia.org/wiki/Display_resolution - "the use of the word resolution here is a misnomer, though common" "resolution properly refers to the pixel density, the number of pixels per unit distance or area, not total number of pixels" See also http://en.wikipedia.org/wiki/Pixel_density Regards, Antony. -- If you were ploughing a field, which would you rather use - two strong oxen or 1024 chickens? - Seymour Cray, pioneer of supercomputing Please reply to the list; please don't CC me.
