Apple has changed the technology type of the iMac displays three times over the years. Customers are confused as to what to choose for ColorMunki Smile, ColorMunki Display, and i1Display Pro. This will explain the way to properly identify the technology type on a given iMac .Apple Display Technology Types:
Prior to 2009, Apple used a CCFL Technology Type in all of their displays...iMacs, Apple Cinema Displays, and laptops as well. The one exception was the 30" Apple Cinema Display which used a "Wide Gamut CCFL" Technology Type. In 2009 and later, all Apple displays went to a "White LED" Technology Type. The iMac display technology has changed recently so please see the notes on the iMac below. The MacBook Pro changed to a new technology in 2016 and the correct Technology Type in ColorMunki Display for the 2016 and later MacBook Pro is: "Generic Type 23". The next update to i1Profiler will add a new Technology Type for 2016 and later MacBook Pros so current i1Display Pro users should stay with the "White LED" Technology Type.
iMac Display Technology Types:
As of late 2015, Apple has changed the technology type in the Retina 5K, 27" and Retina 4K, 21.5" iMacs to an RG Phosphor backlight. As a result, the appropriate technology type to select with the ColorMunki Display is "GB-LED (RG Phosphor)" and "GB LED" with the i1Display Pro (GB LED is the same calibration matrix as RG Phosphor). ColorMunki Smile users will need to stay with "LED". While Apple went to White LED backlit displays in 2009, these two iMac models switched to the RG Phosphor in late 2015. Prior to 2009, iMacs were CCFL backlit displays. To properly identify an RG Phosphor iMac, go to the Apple in the menu bar and select "About this Mac". If the resulting window shows that the iMac is "Late 2015" or newer, it is the RG Phosphor / GB-LED technology type. To summarize the history of iMac Technology Type:
Before 2009 - CCFL
2009 - Mid 2015 - White LED
Retina 4K, 21.5" and 5K, 27" iMacs (Late 2015 and after) - GB-LED (RG Phosphor)