Reference sRGB / Rec.709 Colors
Absolute Color Accuracy Error Plots
Figure 2c below shows the measured on-screen colors just for the iPad mini with Retina Display, which is included separately because of its very large errors within the plot. Thin black lines pair up the more distant Reference Colors and measured colors.
The Reference Colors are all shown as Black circles amd the measured Chromaticities for the Tablets are shown as Red and Blue circles. Color Errors smaller than the appropriate JNCD are not visually noticeable. The 1 JNCD and 3 JNCD are discussed next and appear in both Figures 2a and 2b.
Just Noticeable Color Difference JNCD
Color differences less than 1 JNCD are visually indistinguishable, while values greater than 1 JNCD are visually noticeable when the two colors are touching on-screen. When the colors are not touching and are further apart, the visual threshold for Just Noticing a Color Difference is higher. Here we will use 3 JNCD for the threshold of a visually noticeable display color difference. Any Color Accuracy or Color Error less than 3 JNCD is visually indistinguishable. The sizes of 1 JNCD and 3 JNCD are shown in Figures 2a and 2b below.
Figure 2b Kindle and Nexus Absolute Color Accuracy Error Plots
Figure 2c iPad mini Retina Display Absolute Color Accuracy Error Plots