41 Reference Colors for the sRGB / Rec.709 Color Gamut Standard
Most existing consumer content
is based on the sRGB / Rec.709 Color Gamut Standard.
Figure 2a
below shows 41 Reference Colors for the
Standard sRGB / Rec.709 Color Gamut as White, Gray, and Black circles.
The 10 Black circles on the outer triangle
are the 100% fully Saturated Colors on the periphery.
The 3 inner sets of Gray triangles are the 25%, 50% and 75% Saturated Colors
between the inner White Point and the 100% Saturated Colors on the periphery.
The White circle is the White Point with 0% Color Saturation.
The colors in Figure 2a have been accurately calculated to show the real colors within the sRGB / Rec.709 Gamut - the colors shown in most published Color Gamuts are wildly incorrect. For an in-depth discussion and analysis of these Color Gamuts see this article.
Note that Complementary Colors lie directly across from one another through the White Point.
The 4 sets of triangles are the 25% 50% 75% and 100% Saturated Colors.
Uniform Color Diagrams
All color measurements are plotted on 1976 CIE Uniform Color Diagrams.
Note that the older 1931 CIE Diagrams that are published by many reviewers
are highly non-uniform and are meaningless for Color Accuracy.
Also the often referenced NTSC Color Gamut is from 1953 and has been
obsolete for over 30 years so stop referencing it!
Absolute Color Accuracy Plots
AMOLED Cinema screen mode:
Figure 2b
below shows the measured on-screen colors for the
DCI-P3 Reference Colors.
Basic screen mode:
Figure 2c
below shows the measured on-screen colors for the
sRGB / Rec.709 Reference Colors.
AMOLED Photo screen mode:
Figure 2d
below shows the measured on-screen colors for the
Adobe RGB Reference Colors.
Reference Colors
The
Reference Colors
in
Figures 2b-2d
are all shown as Black circles and the measured
Colors for each of the Screen Modes are shown as Red circles.
Color Errors smaller than the appropriate JNCD are not visually noticeable.
The 1 JNCD and 3 JNCD Errors are discussed next and are shown in the Figures below.
Just Noticeable Color Difference JNCD
The on-screen colors produced by any display can be measured using a
Spectroradiometer together with our proprietary DisplayMate Test Patterns.
The accuracy of the colors can then be calculated using the
1976 CIE Uniform Chromaticity color space and compared to the
eye's sensitivity to color.
We present the color accuracy and errors here in terms of
MPCD Minimum Perceptible Color Difference or
JNCD Just Noticeable Color Difference,
where 1 MPCD = 1 JNCD = Δ(u'v') = 0.0040 on the
CIE 1976 Uniform Chromaticity Scale.
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. The 1 JNCD and 3 JNCD sizes are shown in the Figures below. Any Display Color Error less than 3 JNCD on a display is not visually noticeable and appears perfectly accurate to the eye. For an in-depth discussion and analysis of Absolute Color Accuracy see this article.
The AMOLED Cinema Screen Mode provides an accurate color match to the DCI-P3 Color Gamut.
The largest errors are in the Blue Zone, which is much less important for visual Color Accuracy.
Figure 2c. Basic Screen Mode Absolute Color Accuracy Plots
The Basic Screen Mode provides an accurate color match to the standard sRGB / Rec.709 Color Gamut.
The largest errors are in the Blue Zone,
which is much less important for visual Color Accuracy.
Figure 2d. AMOLED Photo Screen Mode Absolute Color Accuracy Plots
The AMOLED Photo Screen Mode provides an accurate color match to the Adobe RGB Color Gamut.
The largest errors are in the Blue Zone,
which is much less important for visual Color Accuracy.
