Monday, November 02, 2009

New iMac screens - Pixel density considerations

The new value machines amongst the new iMacs are the Core 2 Duo 21.5" models unless you want a fast GPU. They are quite a bit smaller than the 27-inchers, but they can be more ergonomic, they are still full 1080p HD resolution, and just as importantly they have a much larger pixel size than the 27" models. The larger pixel size can be a significant advantage for a desktop, especially for an OS like Snow Leopard which is not resolution independent. In order of increasing pixel density (or smaller pixel size):

15" G4 iMac: 1024 / 12" = 85 ppi
24" iMac: 1920 / 20.4" = 94 ppi
20" iMac: 1680 / 17.1" = 98 ppi
17" iMac: 1440 / 14.4" = 100 ppi
21.5": 1920 / 18.7" = 102 ppi
27": 2560 / 23.5" = 109 ppi
13" MacBook Pro: 1280 / 11.3" = 113 ppi
12" G4 iBook: 1024 / 9" = 114 ppi

As I no longer have the eyes of a teenager, my favourite desktop pixel density for web surfing in Safari is somewhere around 90-100 pixels per inch (ppi). That includes the 20" and 24" iMacs, with the 21.5" coming in very close at 102 ppi. I had a chance to check out the 21.5" and 27" iMacs in person and I found the 21.5" more pleasant for general surfing than the 27" at normal desktop seating distances, at least with Safari. While it's true the 27" is still a lower pixel density than the laptops, people generally sit closer to laptop screens so the higher pixel density is less problematic for laptops than desktops. Luckily, while this is a problem for Safari, it's not as much of a problem with Mozilla Firefox, since Firefox is more easily adjustable. The 27" iMac might just be enough to push to me to Firefox as my primary web browser on the Mac.

We can only hope that the new 27" screen is a hint to full resolution independence to come in OS X 10.7.


Alexey said...

Thank you for publishing valuable information. It helped me to consider what iMac to choose

Anonymous said...

You're dividing horizontal pixel resolution into diagonal screen resolution, and your numbers are off as a result.

Eug said...

No I'm not. I'm dividing the horizontal resolution by the horizontal width.

eg. A 12" iBook is 1024 pixels wide, and 9" wide, and therefore it is 113.8 pixels per inch.

Anonymous said...

Thanks to 21,5" and 27" pixel densities. looks like 21,5" is better to me even is still little small i prefer 1920x1080/1200 with 24" i think. currently i have 22" display with this resolution.