What are the differences between the displays used in the Intel-based "Aluminum" and "White" iMac models? What is the viewable angle and the brightness of each?

When Apple introduced the original "Aluminum" iMac Core 2 Duo line on August 7, 2007, there was immediate outcry from some readers disappointed that the iMac "Core 2 Duo" 2.0 20-Inch (Al) and "Core 2 Duo" 2.4 20-Inch (Al) models had a lower-quality 6-bit "glossy" display with a reduced viewing angle compared to the 8-bit display in the 20-Inch "White" models that these systems replaced. Some disappointed customers went as far as filing suit against Apple over the issue.

The "Late 2009" iMac models -- the iMac "Core 2 Duo" 3.06 21.5-Inch (Late 2009), "Core 2 Duo" 3.06 27-Inch (Late 2009), and "Core i5" 2.66 27-Inch (Late 2009) -- have "glossy" TFT active-matrix LED-backlit LCD displays with 1920x1080 and 2560x1440 native resolutions (16:9). Both displays are 8-bit and use IPS (In-Plane Switching) technology, a considerable improvement for the 21.5-Inch configuration compared to the 20-Inch models replaced. However, it is worth noting that the 27" models are brighter than the 21.5" models (375 cd/m2 compared to 320 cd/m2).

Display size, brightness, contrast ratio, and viewable angle is provided on each individual iMac specs page but to make comparison easier, this information also is provided below in a handy chart:

* Horizontal viewable angle/vertical viewable angle.

† These models use "glossy" displays.

‡ Please note that on August 7, 2007, Apple reported the brightness of the display in these systems in "nits" but quitely changed it a few days later to "cd/m2".

§ Apple originally reported the brightness of the display in these systems as "380 nits" but changed it a few days later to "385 cd/m2."

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What does "nits" mean as a unit of brightness? How does "nits" compare to "cd/m"?

"Nits" and "cd/m2" candela per square meter, but often reported as just "cd/m" -- are both effectively identical measures of luminance. On August 7, 2007, Apple published the brightness of the displays used by the original "Aluminum" iMac Core 2 Duo models in "nits" but quitely changed this a few days later to the previously used "cd/m2" standard. For more information, please refer to the Lighting Design Glossary.