Actual Size Or 100% Not 100%


I am looking to upgrade to a G5 Mac, probably the 17" iMac, and while shopping I've noticed that when I open an application that has rulers (and the page magnification/view is 100% or Actual Size), the rulers/page seem to be shrunken (to about 75-ish%).

I understand why this might happen, at least from a simple math perspective -- If the display pixel density was 72 DPI, AND the software app's assume a 72 DPI standard, the rulers would actually be correct (1" on screen would measure 1").

The display pixel density on the 17" iMac (and most new LCD displays) is obviously higher than 72 DPI (more like 96 or 100?). HOWEVER, it SEEMS that most or all Mac software (including the OS?) still assumes 72 DPI, so things seem shrunken (since the individual pixels are smaller).

I can't seem to find any kind of system preference in OS 10.4 to adjust the DPI the system should be dealing with to whatever the NATIVE DPI of the display is. If I simply adjust the "screen resolution" to something LOWER than NATIVE (thus making the screen image appear larger), the image on the screen is of couse BLURRY (since LCD pixels are finite compared to a CRT's more amorphous pixels, and the sustem is trying to paint a pixel of information across more than one LCD pixel).

HERE'S THE RUB: Microsoft's Windows XP Professional appears to have a way to adjust the DPI setting at the system level -- BUT Apple's Mac OS 10.4 DOESN'T ???

Not one Apple dealer, tech (even actual Apple Inc. techs) or user I've talked to even seems to know what I'm talking about (but the FIRST PC sales rep, at CompUSA, I talked to knew exactly what I was talking about)!

Doesn't it make sense that if you choose 100% view in an application that it would at least come close to 100%?!

Have I lost my mind? Have Mac users and Apple Computer employees suddenly become morons? Is it a conspiracy? Alien mind control rays? If I (gulp) abandon the Mac and switch to Windows, does that mean I'm in league with Satan?


Kevin W.


Registered Bot
Yes. Yes. Possibly. Cottage cheese. That sounds perverted. - Respectively

There's a little program (in the developers stuff) called "Quartz Debug" that will let you do that. Of course it doesn't exactly work. Besides, there's this thing called the "DPI myth". The Mac actually is much more sophisticated than, say, a simple OS such as Win XP. It automatically selects a user interface DPI based on the best scientific research so you don't have to. Silly Windows.

Of course, it's not guaranteed to be correct. And it's always 72 dpi.


P.S. All seriousness aside, there's evidence that Apple is transitioning OS X to a device-independent UI. Let's hope so. In the mean time, perform a quick mental calculation to determine your optimal DPI. And thank your lucky stars you don't have to feed, walk, and water the Win XP search doggie!


Mac Enthusiast
For most applications like Word, set the view to 125% and it'll be in proportion. For the actual size thing in Preview where it doesn't go actual size sometimes, in the Preferences turn off Respect Image DPI for Actual Size. Thats all I had issues with.

And for Christ's sake, take a chill pill.