There have been many extended discussions on this list about this very
topic. If you enter 96ppi in the search field, I bet you get plenty of
All computer display systems use 72ppi as their touchstone for pixel
graphics, but then the physical ppi of the display can be and usually
is much different/denser. Understanding this difference between
physical display density and the math that goes on in the graphics
system can be a real head-scratcher.
It’s an important distinction that Windows uses 96ppi for rasterizing
type to a bitmap, but then uses 72ppi to display the resulting bitmap
text along with all other pixel-based or pixel-sized elements on the
screen. This is one place where type can become larger.
In addition, Windows uses a different method for computing the
bounding box for type, which results in a different amount of apparent
leading between lines of text and often significantly different line-
To add insult to injury, Windows will adjust the physical shapes of
characters to force them to land more neatly on the (96ppi) font-to-
pixel grid. Where Mac OS would draw a fuzzy anti-aliased partial line
just because that’s precisely where the font designer intended the
stroke to go, Windows will move it over a scosh and draw it dense and
black, often completely redesigning the character in the process.
On Aug 12, 2011, at 12:03 PM, chuckamuck wrote:
Windows uses a different default pixel density from Mac. 96ppi as
opposed to 72ppi. This results in the larger type you are seeing.