All of the DisplayMate Display Performance Grades,
Ratings and Awards are based entirely on the extensive objective Lab tests and
measurements that we also publish, so that everyone can judge and compare the
display performance data for themselves as well.
|
Categories
|
Xiaomi
Redmi K40 Pro
|
Comments
|
|
Display Technology
|
OLED
Display
with Diamond
Pixels
6.65 inch
Diagonal / 16.9 cm Diagonal
Excluding the Rounded
Corners
|
Organic Light Emitting Diode
Diamond
Pixels
with Diagonal Sub-Pixel Symmetry.
|
|
Screen Aspect Ratio
|
20 : 9 =
2.22
Higher
Aspect Ratio
Most
Smartphones and Widescreen TVs have 16 : 9 = 1.78
|
Height to Width Aspect Ratio
The Redmi K40 Pro display screen is 25%
longer than
most Smartphones and widescreen 16:9 TV
content.
|
|
Screen Size
|
2.73
x 6.07 inches
6.94 x
15.43 cm
|
Display Width and Height in inches and
cm.
|
|
Screen Area
|
16.6 square
inches / 107 square cm
After
Subtracting the Camera Opening but not the Rounded Corners
|
A better measure of size than the
Diagonal.
|
|
Front Camera Opening Size
|
Front
Camera Opening has less than 0.1 percent of the Screen Area
Diameter
is 0.13 inches / 3.2 mm
|
Front Camera Opening is by the Top Left
of the Screen.
|
|
Supported Color Gamuts
|
Auto mode –
Wide Color Gamut with Higher Contrast
Original DCI-P3 mode – DCI-P3 Standard Color
Gamut
Original sRGB mode – sRGB /
Rec.709 Standard Color Gamut
Saturated
mode – Native OLED Color Gamut with Higher Contrast
Automatic
Color Management for Content with ICC Color Profiles
|
The Redmi K40 Pro supports 2 Standard
Color Gamuts: sRGB and the new wider DCI-P3 Color Gamut that is used in 4K
Ultra HD TV content.
|
|
Display Refresh Rates
|
Display
Refresh Frames Per Second FPS
Normal
FPS: 60 Hz Refresh
High FPS:
120 Hz Refresh for Smoother Scrolling and Motion
|
Higher Refresh Rates improve image
Scrolling
plus Video and Motion Performance in
Apps,
and may reduce Screen Flicker that some
people experience.
|
|
Display Resolution
|
2400 x 1080
pixels
2K+ FHD+
|
Screen Pixel Resolution.
Quad HD can display four 1280x720 HD
images.
|
|
Total Number of Pixels
|
2.6 Mega
Pixels
|
Total Number of Display Pixels.
|
|
Pixels Per Inch PPI
|
395 PPI
with Diamond Pixels
Excellent
|
Sharpness depends on the viewing distance
and PPI.
See this on
the visual acuity for a true Retina Display
|
|
Sub-Pixels Per Inch SPPI
|
Red
279 SPPI
Green
395 SPPI
Blue
279 SPPI
|
Diamond Pixel displays have only half the
number of
Red and Blue Sub-Pixels as RGB Stripe
displays.
At High PPI this is generally not visible
due to
the use of Sub-Pixel Rendering.
|
|
Total Number of Sub-Pixels
|
Red
1.3 Million Sub-Pixels
Green 2.6
Million Sub-Pixels
Blue
1.3 Million Sub-Pixels
|
Diamond Pixel displays have only half the
number of
Red and Blue Sub-Pixels as RGB Stripe
displays.
At High PPI this is generally not visible
due to
the use of Sub-Pixel Rendering.
|
|
20/20 Vision Distance
where Pixels or Sub-Pixels
are Not Resolved
|
8.7
inches / 22.1 cm for White and Green Sub-Pixels with 20/20 Vision
12.3
inches / 31.3 cm for Red and Blue Sub-Pixels with 20/20 Vision
|
For 20/20 Vision the minimum Viewing
Distance
where the screen appears perfectly sharp
to the eye.
At 12 inches from the screen 20/20 Vision
is 344 PPI.
|
|
Display Sharpness
at Typical Viewing Distances
|
Redmi K40
Pro Display appears Perfectly Sharp
Pixels are
not Resolved with 20/20 Vision
at Typical
Viewing Distances of
12 to
18 inches
30 to 46
cm
|
The Typical Viewing Distances for this
screen size
are in the range of 12 to 18 inches or
25 to 46 cm.
Also note that eye’s resolution is much
lower for
Red and Blue color content than White
and Green.
|
|
Appears Perfectly Sharp
at Typical Viewing Distances
|
Yes
|
Typical Viewing Distances are 12 to 18
inches
or 30 to 46 cm for this screen size.
|
|
Overall Display Performance Assessments
This section summarizes
the results for all of the extensive Lab Measurements and Viewing Tests
performed on the display.
See Screen Reflections, Brightness
and Contrast, Colors and Intensities,
Absolute Color Accuracy, Viewing Angles, OLED Spectra
The
Redmi K40 Pro has Automatic Color Management that switches to the appropriate
Color Gamut for Content with ICC Color Profiles.
Here
we provide results for the Auto Color mode, which has a Wide Color Gamut and Higher Image Contrast,
the
Original DCI-P3 mode, which is calibrated for the new DCI-P3 Gamut that is used
in 4K Ultra HD TVs,
and
the Original sRGB mode, which is calibrated for the sRGB / Rec.709 Gamut that is used for most current
consumer photo, video,
web, and computer content.
|
Categories
|
Auto
Color mode
Wide Color
Gamut
|
Original
Color mode
DCI-P3
Content
|
Original
Color mode
sRGB
Content
|
Comments
|
|
Viewing Tests
in Subdued Ambient Lighting
|
Very Good
Images
Photos and
Videos
have Vivid
Color
and Higher
Contrast
Intentionally
Vivid Colors
|
Excellent
Images
Photos and
Videos
have
Excellent Color
and
Accurate Contrast
Accurate
DCI-P3 Content
|
Excellent
Images
Photos and
Videos
have
Excellent Color
and
Accurate Contrast
Accurate
sRGB Content
|
The Viewing Tests examine the accuracy
of
photographic images by comparing the
displays
to a calibrated studio monitor and TV.
|
|
Variation with Viewing Angle
Colors and Brightness
See Viewing Angles
|
Color
Shifts
Small to
Medium
with
Viewing Angle
Small
Brightness Shifts
with
Viewing Angle
|
Color
Shifts
Small to
Medium
with
Viewing Angle
Small
Brightness Shifts
with
Viewing Angle
|
Color
Shifts
Small to
Medium
with
Viewing Angle
Small
Brightness Shifts
with
Viewing Angle
|
The Redmi K40 Pro display has a
relatively small
decrease in Brightness with Viewing
Angle and
relatively small Color Shifts with
Viewing Angle.
See the Viewing Angles section for details.
|
|
Overall Display Assessment
Lab Tests and Measurements
|
Excellent
OLED Display
Vivid Color
Mode
|
Excellent
OLED Display
Accurate
DCI-P3 Content
|
Excellent
OLED Display
Accurate
sRGB Content
|
The Redmi K40 Pro OLED Display performed
very well in the Lab Tests and
Measurements.
|
|
|
|
Absolute Color Accuracy
Measured over Entire Gamut
See Figure 2 and Colors
|
Good Color
Accuracy
Colors
More Saturated
Intentionally
Vivid Colors
|
Excellent
Color Accuracy
Color
Errors are Very Small
Accurate
DCI-P3 Content
|
Excellent
Color Accuracy
Color
Errors are Very Small
Accurate
sRGB Content
|
Absolute
Color Accuracy is measured with a
Spectroradiometer
for 41
Reference Colors
uniformly
distributed within the entire Color Gamut.
See
Figure 2 and Colors for details.
|
|
Image Contrast Accuracy
See Figure 3 and Contrast
|
Very Good
Accuracy
Image
Contrast
Intentionally
Higher
|
Excellent
Accuracy
Image
Contrast
Very
Accurate
|
Excellent
Accuracy
Image
Contrast
Very
Accurate
|
The
Image Contrast Accuracy is determined by
measuring
the Log Intensity Scale and Gamma.
See
Figure 3 and Contrast for details.
|
|
Performance in Ambient Light
Display Brightness
Screen Reflectance
Contrast Rating
See Brightness and Contrast
See Screen Reflections
|
High
Display Brightness
Very Low
Reflectance
High
Contrast Rating
for Ambient
Light
Higher
Brightness with
Auto
Brightness On
|
High
Display Brightness
Very Low
Reflectance
High
Contrast Rating
for Ambient
Light
Higher
Brightness with
Auto
Brightness On
|
High
Display Brightness
Very Low
Reflectance
High
Contrast Rating
for Ambient
Light
Higher
Brightness with
Auto
Brightness On
|
Smartphones
are seldom used in the dark.
Screen
Brightness and Reflectance determine
the
Contrast Rating for High Ambient Light.
See
the Brightness and Contrast section for details.
See
the Screen Reflections section for details.
|
|
Overall Display Calibration
Image and Picture Quality
Lab Tests and Viewing Tests
|
Vivid Color
Mode
Intentionally
Vivid Colors
and Higher
Image Contrast
|
Excellent
Calibration
Accurate
DCI-P3 Content
|
Excellent
Calibration
Accurate
sRGB Content
|
The Redmi K40 Pro has sRGB and DCI-P3
modes
that deliver accurately calibrated
colors and images
and a Vivid Color mode that is preferred
by
some users and for some applications.
|
|
|
Overall Display Grade
Overall
Assessment
|
Overall Xiaomi Redmi K40 Pro
Display Grade is Excellent A+
DisplayMate Best
Smartphone Display Award
with 11 Smartphone
Display Performance Records
including 5 that are
Visually Indistinguishable From Perfect
An Excellent Top Tier
World Class Smartphone Display
|
The Redmi K40 Pro display delivers
Excellent
Image Quality, has both Original sRGB and
Original DCI-P3 modes and an Auto Color
mode with
a Wide Color Gamut, has High Screen
Brightness
and low Reflectance, has good Viewing
Angles, and
is an all around Top Performing
Smartphone Display.
|
|
Vivid Color
Mode
Also Best
for Viewing in
High
Ambient Light
|
Accurate
DCI-P3 Content
For Viewing
4K UHD TV
DCI-P3
Cinema Content
|
Accurate
sRGB mode
For Viewing
Most Content
Photo Video
Movie Web
|
Categories
|
Auto
Color mode
Wide Color
Gamut
|
Original
Color mode
DCI-P3
Content
|
Original
Color mode
sRGB
Content
|
Comments
|
|
Xiaomi Redmi K40 Pro Conclusions: A
Record Setting Impressive Smartphone Display…
The primary goal of this Display Technology Shoot-Out
article series has always been to publicize and promote display
excellence so that consumers, journalists, reviewers, and even manufacturers
are aware of and appreciate the very best in displays and display technology.
We point out which manufacturers and display technologies are leading and
advancing the state-of-the-art for displays by performing comprehensive and
objective scientific Lab Tests and Measurements together with in-depth
analysis. We point out who is leading, who is behind, who is improving, and
sometimes (unfortunately) who is back pedaling.
All of the DisplayMate Display
Performance Grades, Ratings and Awards are based entirely on the extensive
objective Lab tests and measurements that we also publish, so that everyone
can judge and compare the display performance data for themselves as well.
With consumers now spending rapidly increasing amounts
of time watching content on their Smartphones, the shift in emphasis from
primarily improving Display Hardware Performance to enhancing the overall
Display Picture Quality and Color Accuracy is an important step that
DisplayMate Technologies has been pushing for many years in our Display
Technology Shoot-Out article series, so it is great to see
manufactures improving and then competing on these DisplayMate
Lab Measurement Objective Display Performance Metrics.
· All of these Results, Conclusions, and Ratings also apply
to the Redmi K40 Pro+, Mi 11i, and Mi 11X Pro
The Xiaomi
Redmi K40 Pro sets or matches 11 Smartphone Display Performance Records for:
Numerical Display Performance
Differences that are Visually Indistinguishable are considered Matched and
Tied Performance Records.
· Highest Absolute Color Accuracy (0.7
JNCD) – Visually Indistinguishable From Perfect.
· Highest Image Contrast Accuracy and
Intensity Scale Accuracy (2.25
Gamma) – Visually Indistinguishable From Perfect.
·
Smallest Shift in Color Accuracy and Intensity Scale with the
Image Content APL (0.2 JNCD) – Visually
Indistinguishable From Perfect.
·
Smallest Shift in Image Contrast and
Intensity Scale with the Image Content APL (0.02 Gamma) – Visually Indistinguishable From Perfect.
·
Smallest Change in Peak Luminance with the Image Content
Average Picture Level APL (2 percent) – Visually Indistinguishable From Perfect.
·
Highest Full Screen Brightness for OLED Smartphones
(901 nits at 100% APL).
· Highest Peak Display Brightness
(1,320 nits for Low APL).
· Largest Native Color Gamut (111%
DCI-P3 and 139% sRGB / Rec.709 for the Saturated Mode).
· Highest Contrast Ratio (Infinite).
· Lowest Screen Reflectance (4.6
percent).
· Highest Contrast Rating in Ambient
Light (196 for 100% APL and 287 for Peak Brightness).
.
The Xiaomi Redmi K40 Pro earns our Highest
A+ Display Performance Assessment Rating
OLED has evolved into a highly refined and mature display
technology that now produces the best and highest performance displays for
Smartphones.
OLED Display Performance
continues to provide major Record Setting improvements with every new generation.
Xiaomi has concentrated on significantly raising the
on-screen Absolute Picture Quality and Absolute Color Accuracy of the OLED display by
implementing Precision Factory Display Calibration,
moving the overall Redmi K40 Pro Display Performance
up to Record Setting Outstanding Levels with
close to Text Book Perfect Calibration Accuracy
that is Visually Indistinguishable From Perfect.
DisplayMate Display Performance Ratings:
All of the Results in this article are based Entirely
on our Objective and Extensive DisplayMate Lab Tests and Measurements that
are all listed in the sections below.
· To get a DisplayMate A Display
Performance Rating the display must get All Green [Very Good to Excellent]
Ratings for All of the Display Tests and Measurements [except for Color
Shifts at 30 degrees Viewing Angle, which are deemed less important].
· Then to get a DisplayMate A+ Display
Performance Rating the Average Absolute Color Accuracy and the Average Absolute
Color Accuracy Shifts with Average Picture Level APL must All be less
than 1.0 JNCD, and the Largest Color Errors must All be less than 3.0
JNCD.
The Redmi K40 Pro delivers
Uniformly Consistent Top Tier Display
Performance and receives All Green [Very Good to Excellent] Ratings in All DisplayMate Lab Test Display Performance and Accuracy
Categories and has Absolute Color
Accuracy much better than 1.0 JNCD.
The Redmi K40 Pro display meets all of the criteria and
requirements for a DisplayMate A+ Grade, earning DisplayMate’s Highest
Overall Display Assessment Rating and Highest Display Performance Grade of
A+.
· All
of these Results, Conclusions, and Ratings also apply to the Redmi K40 Pro+,
Mi 11i, and Mi 11X Pro.
DisplayMate Display Performance Rating and
Best Smartphone Display Award
Based on our extensive Lab Tests and Measurements the Redmi K40 Pro
has a Very Impressive Excellent Top Tier World Class Smartphone Display
with close to Text Book Perfect Calibration
Accuracy and Performance that is Visually
Indistinguishable From Perfect. Based
on our objective Lab Tests and Measurements the Redmi
K40 Pro receives a DisplayMate Best
Smartphone Display Award earning DisplayMate’s highest ever Display Performance Grade of A+ and setting or
matching 11 Smartphone Display Performance Records
including 5 that are Visually
Indistinguishable From Perfect that are listed above.
· All of these Results, Conclusions, and Ratings also apply
to the Redmi K40 Pro+, Mi 11i, and Mi 11X Pro
The Redmi K40 Pro, Pro+, Mi
11i, and Mi 11X Pro join the very select Top Tier of Smartphone Displays
which all provide Close to Text Book Perfect
Calibration Accuracy and Performance that is Visually Indistinguishable From
Perfect, so they all received and maintain Concurrent DisplayMate Best
Smartphone Display Awards. All are
Excellent State-of-the-Art Displays, each is better in some Display
Performance Categories, but None are Best in All the Display Performance
Categories. Note that measured numerical display performance differences that
are Visually Indistinguishable are equivalent.
As Display Performance continues to improve we have and
will continue to raise the Performance Levels necessary to receive a
DisplayMate Best Smartphone Display Award and an A+ Display Rating, so The Top Tier of Smartphone Displays will continue to
evolve and change with each new display generation, but only the Very Best
Displays will continue to receive A+ Ratings each year.
|
|
Screen Reflections
All display screens are mirrors good enough to use
for personal grooming – but that is actually a very bad feature…
We measured the light reflected from all directions
and also direct mirror (specular) reflections, which are much more
distracting and cause more eye strain. Many
Smartphones still have greater than 10 percent reflections that make
the screen much harder to read even in moderate
ambient light levels, requiring ever higher brightness settings that
waste precious battery power. Manufacturers should
reduce the mirror reflections with anti-reflection coatings and
matte or haze surface finishes.
Our Lab Measurements include Average
Reflectance for Ambient Light from All Directions and for Mirror Reflections.
We use an Integrating Hemisphere and a
highly collimated pencil light beam together with a Spectroradiometer.
Note that the Screen
Reflectance is exactly the same for all of the Redmi K40 Pro Color Modes.
The Redmi K40 Pro has close to the
lowest Screen Reflectance level that we have ever measured for a Smartphone.
These results are extremely important
for screen readability, picture quality, and color accuracy in ambient light.
|
Categories
|
Redmi
K40 Pro
|
Comments
|
|
Average Screen Reflection
Light From All Directions
|
4.6 percent
for
Ambient Light Reflections
Excellent
|
Measured using an Integrating Hemisphere
and
a Spectroradiometer.
The lowest value we have ever measured
for a Smartphone is 4.3 percent.
|
|
Mirror Reflections
Percentage of Light Reflected
|
5.6
percent
for Mirror Reflections
Very Good
|
These are the most annoying types of
Reflections.
Measured using a Spectroradiometer and a
narrow
collimated pencil beam of light
reflected off the screen.
The lowest value we have ever measured
for a Smartphone is 5.3 percent.
|
|
Brightness and Contrast
The Contrast Ratio
is the specification that gets the most attention, but it only applies for
low ambient light, which is seldom
the case for mobile displays.
Much more important is the Contrast
Rating for High Ambient Light, which indicates how easy it is to read
the screen under
high ambient lighting and depends on both
the Maximum Brightness and the Screen Reflectance. The larger the better.
The display’s actual on-screen Contrast Ratio changes with the Ambient Light lux
level and is proportional to the Contrast Rating.
|
Categories
|
Auto
Color mode
Wide Color
Gamut
|
Original
Color mode
DCI-P3
Content
|
Original
Color mode
sRGB
Content
|
Comments
|
|
Home Screen Peak Brightness
Measured for White
|
Brightness
563 cd/m2
Excellent
|
Brightness
476 cd/m2
Very Good
|
Brightness
476 cd/m2
Very Good
|
The Peak Brightness for White on the
Home Screen.
|
|
Measured Average Brightness
50% Average Picture Level
|
Brightness
562 cd/m2
Excellent
|
Brightness
464 cd/m2
Very Good
|
Brightness
464 cd/m2
Very Good
|
This is the Brightness for typical
screen content
that has a 50% Average Picture Level.
|
|
Measured Full Brightness
100% Full Screen White
|
Brightness
505 cd/m2
Excellent
|
Brightness
465 cd/m2
Very Good
|
Brightness
469 cd/m2
Very Good
|
This is the Brightness for a screen that
is entirely
all white with 100% Average Picture
Level.
|
|
Measured Peak Brightness
1% Average Picture Level
|
Brightness
651 cd/m2
Excellent
|
Brightness
458 cd/m2
Very Good
|
Brightness
458 cd/m2
Very Good
|
This is the Peak Brightness for a screen
that
has only a tiny 1% Average Picture
Level.
|
|
Dynamic Brightness
Change in Luminance with
Average Picture Level APL
|
22 percent
Decrease
Intentionally
Large
|
2 percent
Decrease
Excellent
|
2 percent
Decrease
Excellent
|
This is the percent Brightness decrease
with APL
Average Picture Level. Ideally should be
0 percent.
|
|
Low Ambient Light
|
|
Lowest Peak Brightness
Super Dimming Mode
Brightness Slider to Minimum
|
2 cd/m2
For Very
Low Light
|
2 cd/m2
For Very
Low Light
|
2 cd/m2
For Very
Low Light
|
This is the Lowest Brightness with the
Slider set to
Minimum. This is useful for working in
very dark
environments. Picture Quality remains
Excellent.
|
|
Black Brightness at 0 lux
at Maximum Brightness Setting
|
0 cd/m2
Outstanding
|
0 cd/m2
Outstanding
|
0 cd/m2
Outstanding
|
Black Brightness is important for Low
Ambient Light,
which is seldom the case for mobile
devices.
|
|
Contrast Ratio at 0 lux
Relevant for Low Ambient Light
|
Infinite
Outstanding
|
Infinite
Outstanding
|
Infinite
Outstanding
|
Only relevant for Low Ambient Light,
which is seldom the case for mobile
devices.
|
|
Always-On Display Mode
White Luminance
|
Low 5
cd/m2
High 59
cd/m2
|
Low 5
cd/m2
High 56
cd/m2
|
Low 5
cd/m2
High 56
cd/m2
|
Displayed image content when the
Smartphone
is in Standby Mode.
|
|
High Brightness Mode
Automatic Brightness in High Ambient
Light
|
|
Measured High Brightness Mode
50% Average Picture Level
|
High
Brightness Mode
1,043 cd/m2
Excellent
|
High
Brightness Mode
968 cd/m2
Excellent
|
High
Brightness Mode
968 cd/m2
Excellent
|
This is the Brightness for typical
screen content
that has a 50% Average Picture Level.
|
|
Measured High Brightness Mode
100% Full screen White
|
High
Brightness Mode
901 cd/m2
Excellent
|
High
Brightness Mode
845 cd/m2
Excellent
|
High
Brightness Mode
845 cd/m2
Excellent
|
This is the Brightness for a screen that
is entirely
all white with 100% Average Picture
Level.
|
|
Measured High Brightness Mode
1% Average Picture Level
|
High
Brightness Mode
1,320 cd/m2
Excellent
|
High
Brightness Mode
1,190 cd/m2
Excellent
|
High Brightness
Mode
1,190 cd/m2
Excellent
|
This is the Peak Brightness for a screen
that
has only a small 1% Average Picture
Level.
|
|
High Ambient Light Contrast Rating
|
|
Contrast Rating
for High Ambient Light
The Higher the Better
for Screen Readability
in High Ambient Light
|
110 – 142
With Manual
Brightness
Very Good
196 – 287
High
Brightness Mode
Excellent
|
100 – 101
With Manual
Brightness
Very Good
184 – 259
High
Brightness Mode
Excellent
|
100 – 102
With Manual
Brightness
Very Good
184 – 259
High
Brightness Mode
Excellent
|
Depends on the Screen Reflectance and
Brightness.
Defined as Maximum Brightness / Average Reflectance.
The display’s actual on-screen Contrast
Ratio
changes with the Ambient Light lux level
and
is proportional to the Contrast Rating.
|
|
Screen Readability
in High Ambient Light
|
Very Good A
With Manual
Brightness
Excellent A+
With Auto
Brightness On
|
Very Good A
With Manual
Brightness
Excellent A+
With Auto
Brightness On
|
Very Good A
With Manual
Brightness
Excellent A+
With Auto
Brightness On
|
Indicates how easy it is to read the
screen
under High Ambient Lighting. Depends on
both the Screen Reflectance and
Brightness.
See High
Ambient Light Screen Shots
|
|
Colors and Intensities
The Color Gamut, Intensity
Scale, and White Point determine the
quality and accuracy of all displayed images and all
the image
colors. Bigger is definitely Not Better because the display needs to match
all the Standards that were used
when the content was produced.
The Redmi K40 Pro has
Automatic Color Management that switches to the appropriate Color Gamut for
Content with ICC Color Profiles.
The Redmi K40 Pro also has a Saturated Color mode
with the Native Color Gamut of the OLED Display,
which is 111% of the DCI-P3 Gamut and 139% of the sRGB Gamut.
|
Categories
|
Auto
Color mode
Wide Color
Gamut
|
Original
Color mode
DCI-P3
Content
|
Original
Color mode
sRGB
Content
|
Comments
|
|
Color of White
Color Temperature in degrees
Measured in the dark at 0 lux
The White
Point is Adjustable
with the Reading Mode
Adaptive Colors Mode
Interactive Touch Screen
|
7,620 K
2.9 JNCD
from D65 White
Intentionally
Bluish Mode
See Figure
1
|
6,460 K
0.7 JNCD
from D65 White
Very Close
to Standard
Excellent
Accurate
White Point
See Figure
1
|
6,460 K
0.7 JNCD
from D65 White
Very Close
to Standard
Excellent
Accurate
White Point
See Figure
1
|
D65 with 6,500 K is the standard color
of White
for most Consumer Content and needed for
accurate color reproduction of all
images.
JNCD is a Just Noticeable Color Difference.
White Point accuracy is more critical than
other colors.
See Figure
1 for the plotted White Points.
See Figure 2 for the
definition of JNCD.
|
|
Color Gamut
Measured in the dark at 0 lux
See Figure
1
|
104 percent
DCI-P3
Cinema Gamut
Intentionally
Vivid Colors
131 percent
sRGB /
Rec.709 Gamut
Intentionally
Vivid Colors
See Figure
1
|
102 percent
DCI-P3
Cinema Gamut
Very Close
to Standard
Excellent
Accurate
DCI-P3 Content
See Figure
1
|
104 percent
sRGB /
Rec.709 Gamut
Very Close
to Standard
Excellent
Accurate
sRGB Content
See Figure 1
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Most current consumer content uses sRGB /
Rec.709.
The new 4K UHD TVs and Digital Cinema use
DCI-P3.
A Wide Color Gamut is useful in High
Ambient Light
and for some applications. It can be used
with Color
Management to dynamically change the
Gamut.
See Figure 1
|
|
Absolute Color Accuracy
|
|
Absolute Color Accuracy
Average Color Error at 0 lux
For 41 Reference Colors
Just Noticeable Color Difference
See Figure 2
|
Average
Color Error
From sRGB
/ Rec.709
Δ(u’v’)
= 0.0223
5.6 JNCD
Intentionally
Vivid Colors
Vivid Color
Mode
See Figure 2
|
Average
Color Error
From
DCI-P3
Δ(u’v’)
= 0.0027
0.7 JNCD
Excellent
Accuracy
Accurate
DCI-P3 Content
See Figure 2
|
Average Color Error
From sRGB
/ Rec.709
Δ(u’v’)
= 0.0033
0.8 JNCD
Excellent
Accuracy
Accurate
sRGB Content
See Figure 2
|
JNCD is a Just Noticeable Color Difference.
See Figure 2 for the
definition of JNCD and for the
Accuracy Plots showing
the measured Color Errors.
Color Errors below 2.0 JNCD are
Excellent.
Color Errors below 3.5 JNCD are Very
Good.
Color Errors 3.5 to 7.0 JNCD are
Good.
Color Errors above 7.0 JNCD are
Poor.
|
|
Absolute Color Accuracy
Largest Color Error at 0 lux
For 41 Reference Colors
Just Noticeable Color Difference
See Figure 2
|
Largest Color Error
From sRGB
/ Rec.709
Δ(u’v’)
= 0.0511
12.8 JNCD
for 100%
Red
Intentionally
Vivid Colors
Vivid Color
Mode
See Figure 2
|
Largest Color Error
From
DCI-P3
Δ(u’v’)
= 0.0092
2.3 JNCD
for 75%
Blue
Very Good
Accuracy
Accurate
DCI-P3 Content
See Figure 2
|
Largest Color Error
From sRGB
/ Rec.709
Δ(u’v’)
= 0.0089
2.2 JNCD
for 100%
Blue-Magenta
Very Good
Accuracy
Accurate
sRGB Content
See Figure 2
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JNCD is a Just Noticeable Color Difference.
See Figure 2 for the
definition of JNCD and for the
Accuracy Plots showing
the measured Color Errors.
Color Errors below 2.0 JNCD are
Excellent.
Color Errors below 3.5 JNCD are Very
Good.
Color Errors 3.5 to 7.0 JNCD are
Good.
Color Errors above 7.0 JNCD are
Poor.
|
|
Changes in Absolute Color Accuracy with Average Picture Level APL
Measured Shifts in the Absolute Color Accuracy with Image Content
from Low 1% APL to High 50% APL
|
|
Shift in the Color of White
Just Noticeable Color Difference
See Figure 4
|
White Point
Color Shift
from Low
to High APL
Δ(u’v’)
= 0.0026
0.7 JNCD
Excellent
|
White Point
Color Shift
from Low
to High APL
Δ(u’v’)
= 0.0018
0.4 JNCD
Excellent
See Figure 4
|
White Point
Color Shift
from Low
to High APL
Δ(u’v’)
= 0.0013
0.3 JNCD
Excellent
See Figure 4
|
JNCD is a Just Noticeable Color Difference
See Figure 2 for the
definition of JNCD.
See Figure 4 for the
measured Color Shifts.
Color Shifts below 2.0 JNCD are
Excellent
Color Shifts below 3.5 JNCD are Very
Good.
Color Shifts 3.5 to 7.0 JNCD are
Good.
Color Shifts above 7.0 JNCD are
Poor.
|
|
Average Color Shift
For 41 Reference Colors
Just Noticeable Color Difference
See Figure 4
|
Auto Color
mode
Intentionally
Variable
|
Average
Color Shift
from Low
to High APL
Δ(u’v’)
= 0.0013
0.3 JNCD
Excellent
See Figure 4
|
Average
Color Shift
from Low
to High APL
Δ(u’v’)
= 0.0009
0.2 JNCD
Excellent
See Figure 4
|
JNCD is a Just Noticeable Color Difference.
See Figure 2 for the
definition of JNCD.
See Figure 4 for the
measured Color Shifts.
Color Shifts below 2.0 JNCD are
Excellent
Color Shifts below 3.5 JNCD are Very
Good.
Color Shifts 3.5 to 7.0 JNCD are
Good.
Color Shifts above 7.0 JNCD are
Poor.
|
|
Largest Color Shift
For 41 Reference Colors
Just Noticeable Color Difference
See Figure 4
|
Auto Color
mode
Intentionally
Variable
|
Largest Color Shift
from Low
to High APL
Δ(u’v’)
= 0.0024
0.6 JNCD
for 75%
Cyan-Blue
Excellent
See Figure 4
|
Largest Color Shift
from Low
to High APL
Δ(u’v’)
= 0.0020
0.5 JNCD
for 75%
Blue
Excellent
See Figure 4
|
JNCD is a Just Noticeable Color Difference
See Figure 2 for the
definition of JNCD.
See Figure 4 for the
measured Color Shifts.
Color Shifts below 2.0 JNCD are
Excellent
Color Shifts below 3.5 JNCD are Very
Good.
Color Shifts 3.5 to 7.0 JNCD are
Good.
Color Shifts above 7.0 JNCD are
Poor.
|
|
|
|
Dynamic Brightness
Change in Luminance with
Average Picture Level APL
|
22 percent
Decrease
Intentionally
Large
|
2 percent
Decrease
Excellent
|
2 percent
Decrease
Excellent
|
This is the percent Brightness decrease
with APL
Average Picture Level. Ideally should be
0 percent.
|
|
Intensity Scale and
Image Contrast
See Figure
3
|
Smooth and
Straight
Very Good
Slightly
Too Steep
Intentionally
Steeper
|
Very
Smooth and Straight
Excellent
Very
Accurate
See Figure 3
|
Very
Smooth and Straight
Excellent
Very
Accurate
See Figure 3
|
The Intensity Scale controls image
contrast needed
for accurate Image Contrast and Color
reproduction.
See Figure
3
|
|
Gamma for the Intensity Scale
Larger has more Image Contrast
See Figure
3
|
Gamma 2.33
Very Good
Gamma
Intentionally High
|
Gamma 2.25
Excellent
Gamma Very
Accurate
|
Gamma 2.25
Excellent
Gamma Very
Accurate
|
Gamma is the log slope of the Intensity
Scale.
Gamma of 2.20 is the standard and needed
for
accurate Image Contrast and Color
reproduction.
See Figure
3
|
|
Image Contrast Accuracy
|
Very Good
|
Excellent
|
Excellent
|
See Figure
3
|
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Viewing Angles
The variation of
Brightness, Contrast, and Color with Viewing Angle is especially important
for Smartphones because
of their larger screen
and multiple viewers. The typical manufacturer 176+ degree specification for
LCD Viewing Angle
is nonsense because that
is where the Contrast Ratio falls to a miniscule 10. For most LCDs there are
substantial
degradations at less
than ±30 degrees, which is not an atypical Viewing Angle for Smartphones and
Tablets.
The
Viewing Angle variations are essentially identical for all of the Redmi K40
Pro Color Modes.
Note
that the Viewing Angle performance is also very important for a single viewer
because the Viewing Angle can vary
significantly
based on how the Smartphone is held. The Viewing Angle can be very large if
resting on a table or desk.
· The Redmi K40 Pro display has a Brightness (Luminance)
fall off with Viewing Angle that is much smaller than the best LCD displays.
Color Shifts:
The variation of
Brightness, Contrast, and Color with Viewing Angle is especially important
for Smartphones because
of their larger screen
and multiple viewers. The typical manufacturer 176+ degree specification for
LCD Viewing Angle
is nonsense because that
is where the Contrast Ratio falls to a miniscule 10. For most LCDs there are
substantial
degradations at less
than ±30 degrees, which is not an atypical Viewing Angle for Smartphones and
Tablets.
· The White Point Color Shift is the most viewer noticeable
Color Shift with Viewing Angle because it is often the screen background.
The Redmi K40 Pro has a small White Shift of just 2.1 JNCD at 30 degrees, which is unlikely to be
noticeable.
·
The Color Shifts throughout the entire Color
Gamut vary as combinations of the Primary Color Shifts.
·
The Color Shift for the Red Primary at 30 degrees
Viewing Angle is 4.2 JNCD, somewhat larger than the 3.5 JNCD limit for a
Green
Very Good Rating. This might be somewhat noticeable for some image content
but not objectionable.
·
The Color Shift for the Blue Primary at 30
degrees Viewing Angle is 6.8 JNCD, much larger than the 3.5 JNCD limit for a
Green
Very Good Rating. But Color Shifts in the
Blue Region are less visually noticeable as discussed in this article
Almost
all current model OLED Smartphone Displays have either 1 or 2 Primary Color
Shift Yellow ratings.
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Categories
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Auto
Color mode
Wide Color
Gamut
|
Original
Color mode
DCI-P3
Content
|
Original
Color mode
sRGB
Content
|
Comments
|
|
Brightness Decrease
at a 30 degree Viewing Angle
|
27 percent
Decrease
Small
Decrease
Very Good
|
Most screens become less bright when
tilted.
LCD decrease is generally greater than 50
percent.
|
|
Contrast Ratio at 0 lux
at a 30 degree Viewing Angle
|
Infinite
Contrast Ratio
Outstanding
|
A measure of screen readability when the
screen
is tilted under low ambient lighting.
|
|
White Point Color Shift
at a 30 degree Viewing Angle
|
Small Color
Shift
Δ(u’v’)
= 0.0086
2.1 JNCD
Very Good
|
JNCD is a Just Noticeable Color Difference.
See Figure 2 for the
definition of JNCD.
Color Shifts below 3.5 JNCD are Very
Good
|
|
Color Shifts for the Primaries
|
|
Red Primary Color Shift
at a 30 degree Viewing Angle
|
Medium
Color Shift
Δ(u’v’)
= 0.0169
4.2 JNCD
Good
|
JNCD is a Just Noticeable Color Difference.
See Figure 2 for the
definition of JNCD.
Color Shifts 3.5 to 7.0 JNCD are
Good.
|
|
Green Primary Color Shift
at a 30 degree Viewing Angle
|
Small Color
Shift
Δ(u’v’)
= 0.0121
3.0 JNCD
Very Good
|
JNCD is a Just Noticeable Color Difference.
See Figure 2 for the
definition of JNCD.
Color Shifts below 3.5 JNCD are Very
Good.
|
|
Blue Primary Color Shift
at a 30 degree Viewing Angle
|
Medium
Color Shift
Δ(u’v’)
= 0.0272
6.8 JNCD
Good
|
JNCD is a Just Noticeable Color Difference.
See Figure 2 for the
definition of JNCD.
Color Shifts 3.5 to 7.0 JNCD are
Good.
|
|
|
|
Color Shifts for Color Mixtures
at a 30 degree Viewing Angle
Reference Brown (255, 128, 0)
|
Small
Color Shift
Δ(u’v’)
= 0.0077
1.9 JNCD
Excellent
|
JNCD is a Just Noticeable Color Difference.
Color Shifts for non-IPS LCDs are about 10
JNCD.
Reference Brown is a good indicator of
color shifts
with angle because of unequal drive
levels and
roughly equal luminance contributions
from Red
and Green. See Figure 2 for the
definition of JNCD.
|
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Display Spectra
The Display Spectra for the Auto, sRGB and DCI-P3 Color Modes and for the Reading Mode are measured in Figure 5 below.
The Display White Point is Adjustable:
with the Reading Mode, Adaptive Colors Mode, and Interactive Touch
Screen.
· The Reading Mode is designed to change
the color balance of the display in order to reduce the amount of Blue Light
produced by the display,
which some recent research indicates can affect how well users sleep
afterwards.
The
White Point can shift down to a Warm 3,960 K. See Figure 5.
· The Adaptive Colors Mode automatically
changes the White Point and color balance of the display based on real-time
measurements of the
Color of the Ambient Light falling on the screen. The idea is to make the
display behave more like
paper reflecting
Ambient Light and taking on its Color. It is implemented with an Ambient
Light Sensor that measures
the Color of the
Ambient Light in addition to its Brightness.
The White Point can shift between 3,800 – 6,950 K for the
Original sRGB and DCI-P3 Modes, and 4,150 – 8,250 K for the Auto Mode.
· The Interactive Touch
Screen in Display Settings allows the White Point to be chosen from a
Color Map or Buttons.
The
White Point can shift between 5,950 – 7,000 K for the Original sRGB and
DCI-P3 Modes, and 6,700 – 8,250 K for the Auto Mode.
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