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HDR10 21-Point Grayscale for specific 'nit' levels.
As we know in the HDR measurements world, 235 (8-bit) in LEGAL range represent 100% of the PQ EOTF with 10000 nits as a target.
When we want to measure the HDR grayscale performance, the standard method is to measure with 21-Point (16-235), so 0-10000 nits range.
However, movies mastered mainly using 1000/4000 nits mastering monitors (2000 nit also and soon 5000 nits), so any measurement above that peak output is not really required.
The 'regular/defacto' method we use to generate patterns is to send 1000 or 4000 nits mastering monitor peak metadata using an HDR10 Pattern Generator, PGenerator with HD Fury, or PGenerator with LG's 2020/2021 HDMI Override.
Since the typical method of evaluating HDR10 Grayscale has a 0-10000 nit range, the patch generator will display a lot of patterns above 1000 or 4000 nits, so we are using fewer points at the range we are interesting to measure.
For example, see a regular 0-10000 nit (16-235) patchset below:
The 16th patch (0 is black) will generate 180 code level, with a target Y of 973.123 nits. It's 74.89% of the PQ.
When we want to measure with 1000 nit metadata, we are interested to see how our TV responds to a 1000 nit movie metadata.
When we use a bright LCD/LED with a peak output higher than 1000 nits and the TV can count the incoming metadata from the HDMI input, it will not apply any roll-off to the PQ EOTF.
When we use a WRGB based OLED, the peak output is less than 1000 nits; the TV will apply a roll-off to avoid clipping of highlights until 1000 nits.
LG OLEDs 2019/2020/2021 have PQ Upload parameters; we can upload the calibrated peak output nits number and decide if we want to clip or roll-off or define the percentage the TV will start to roll off. (2018 LG's have a default 750 nit number baked, we can't change that)
However, when we take measurements of 21-Point Grayscale using regular methods, we waste five patches; as you can see, only 16 patches will measure the TV performance up to 1000 nits.
When we want to limit the peak level of patterns to a specific nit level, then we can use the Limit Range @ ColourSpace Settings.
Using ''Limit Range'' we can define the max 8-bit digital code values we want as our maximum generated patch, so our 21-Point Grayscale will measure only the grayscale steps only at the range we want to evaluate.
By enabling Limit Range with 181 value, we can take 21-Point Grayscale for 0-1000 nit range, so we will have more points to measure and see with more detail when the roll-off will start or how the display is tracking the PQ up to 1000 nits.
It's not only a waste of time with regular workflow, but we are also increasing the panel temperature because we will measure patches our display can't reproduce or we are interested in measuring.
Below you will see some examples of Limit Range values you can set to limit the measurements to specif nits, for various TVs evaluation:
~100 nits = code value 127, its the 50.7% of PQ (98.8 nits)
~200 nits = code value 143, its the 58% of PQ (201.5 nits)
~300 nits = code value 152, its the 62% of PQ (297.6 nits)
~400 nits = code value 159, its the 65.3% of PQ (401.5 nits)
~500 nits = code value 164, its the 67.6% of PQ (496.4 nits)
~600 nits = code value 168, its the 69.4% of PQ (587.8 nits)
~700 nits = code value 172, its the 71.2% of PQ (695.6 nits)
~750 nits = code value 174, its the 72% of PQ (756.6 nits)
~800 nits = code value 175, its the 72.6% of PQ (789.1 nits)
~850 nits = code value 177, its the 73.5% of PQ (858.1 nits)
~900 nits = code value 178, its the 74% of PQ (894.9 nits)
~950 nits = code value 179, its the 74.4% of PQ (933.2 nits)
~1000 nits = code value 181, its the 75.3% of PQ (1014.8 nits)
~2000 nits = code value 198, its the 82.6% of PQ (1982.8 nits)
~4000 nits = code value 214, its the 90.4% of PQ (4057.5 nits)
How to find the 8-bit value of the specific nit level we want?
Set @ ColourSpace ''Settings'' the 'ST.2084 REC.2020' as Target Gamut / EOTF.
Patchscale Legal / 8bit:
Tick from ''Manual Measure'' the radio buttons of the R/G/B color channels to see grayscale triplets.
Use the up/down arrow keys from the keyboard to change the +-1 digital 8-bit value while you watch the Target Y.
The 170 8-bit code value has 639 nits target Y:
How to perform manual measurements for 21-Point Grayscale for specific nit level?
If you want to limit the displayed patches to 750 nits, find the closer 8-bit digital code value using the arrow keys, the 174 (756 nits), see the animated PNG:
Go again to the ColourSpace ''Settings'' and enable 'Limit Range' 174.
Go to 'Manual Measure window:
Define the steps you want, for example, 21-Point.
Move the RGB sliders at the lowest position (16.16.16).
Press to measure; it will measure black.
You can select the next patch using a left mouse click at the area with the red dot.
You can select the next/previous point using single left mouse clicks at the area above/below the three sliders.
How to perform HDR10 21-Point Grayscale sweep using a patchlist for specific nit levels?
Using the ''Limit Range'' function of ColourSpace, I have created 15 HDR10 patchlists for 21-Point Grayscale.
ColourSpace users can load any of those patchlists to measure 21-Point HDR10 Grayscale with a limit to the nits they want.
It will not require to enable Limit Range.
Select the ST.2048 REC.2020 as target colorspace, keep the Limit range unticked, select LEGAL patchscale for PGenerator users (or other pattern generator users with video level output) @ ColourSpace Settings.
Add metadata using HDFury GUI to the HD Fury Device you have connected at the output of PGenerator or use LG 2020/2021 HDMI Override menu to force/setup HDR10 metadata details.
Use the Manual Measure Window and load each patchset; I have posted picture examples about how to load a patchlist in this post's ''instructions'' area.
HDR10 21-Point Grayscale Patchlist Download Link
You can download the ZIP with 15 HDR10 21-Point Grayscale Patchsets here.
As we know in the HDR measurements world, 235 (8-bit) in LEGAL range represent 100% of the PQ EOTF with 10000 nits as a target.
When we want to measure the HDR grayscale performance, the standard method is to measure with 21-Point (16-235), so 0-10000 nits range.
However, movies mastered mainly using 1000/4000 nits mastering monitors (2000 nit also and soon 5000 nits), so any measurement above that peak output is not really required.
The 'regular/defacto' method we use to generate patterns is to send 1000 or 4000 nits mastering monitor peak metadata using an HDR10 Pattern Generator, PGenerator with HD Fury, or PGenerator with LG's 2020/2021 HDMI Override.
Since the typical method of evaluating HDR10 Grayscale has a 0-10000 nit range, the patch generator will display a lot of patterns above 1000 or 4000 nits, so we are using fewer points at the range we are interesting to measure.
For example, see a regular 0-10000 nit (16-235) patchset below:
The 16th patch (0 is black) will generate 180 code level, with a target Y of 973.123 nits. It's 74.89% of the PQ.
When we want to measure with 1000 nit metadata, we are interested to see how our TV responds to a 1000 nit movie metadata.
When we use a bright LCD/LED with a peak output higher than 1000 nits and the TV can count the incoming metadata from the HDMI input, it will not apply any roll-off to the PQ EOTF.
When we use a WRGB based OLED, the peak output is less than 1000 nits; the TV will apply a roll-off to avoid clipping of highlights until 1000 nits.
LG OLEDs 2019/2020/2021 have PQ Upload parameters; we can upload the calibrated peak output nits number and decide if we want to clip or roll-off or define the percentage the TV will start to roll off. (2018 LG's have a default 750 nit number baked, we can't change that)
However, when we take measurements of 21-Point Grayscale using regular methods, we waste five patches; as you can see, only 16 patches will measure the TV performance up to 1000 nits.
When we want to limit the peak level of patterns to a specific nit level, then we can use the Limit Range @ ColourSpace Settings.
Using ''Limit Range'' we can define the max 8-bit digital code values we want as our maximum generated patch, so our 21-Point Grayscale will measure only the grayscale steps only at the range we want to evaluate.
By enabling Limit Range with 181 value, we can take 21-Point Grayscale for 0-1000 nit range, so we will have more points to measure and see with more detail when the roll-off will start or how the display is tracking the PQ up to 1000 nits.
It's not only a waste of time with regular workflow, but we are also increasing the panel temperature because we will measure patches our display can't reproduce or we are interested in measuring.
Below you will see some examples of Limit Range values you can set to limit the measurements to specif nits, for various TVs evaluation:
~100 nits = code value 127, its the 50.7% of PQ (98.8 nits)
~200 nits = code value 143, its the 58% of PQ (201.5 nits)
~300 nits = code value 152, its the 62% of PQ (297.6 nits)
~400 nits = code value 159, its the 65.3% of PQ (401.5 nits)
~500 nits = code value 164, its the 67.6% of PQ (496.4 nits)
~600 nits = code value 168, its the 69.4% of PQ (587.8 nits)
~700 nits = code value 172, its the 71.2% of PQ (695.6 nits)
~750 nits = code value 174, its the 72% of PQ (756.6 nits)
~800 nits = code value 175, its the 72.6% of PQ (789.1 nits)
~850 nits = code value 177, its the 73.5% of PQ (858.1 nits)
~900 nits = code value 178, its the 74% of PQ (894.9 nits)
~950 nits = code value 179, its the 74.4% of PQ (933.2 nits)
~1000 nits = code value 181, its the 75.3% of PQ (1014.8 nits)
~2000 nits = code value 198, its the 82.6% of PQ (1982.8 nits)
~4000 nits = code value 214, its the 90.4% of PQ (4057.5 nits)
How to find the 8-bit value of the specific nit level we want?
Set @ ColourSpace ''Settings'' the 'ST.2084 REC.2020' as Target Gamut / EOTF.
Patchscale Legal / 8bit:
Tick from ''Manual Measure'' the radio buttons of the R/G/B color channels to see grayscale triplets.
Use the up/down arrow keys from the keyboard to change the +-1 digital 8-bit value while you watch the Target Y.
The 170 8-bit code value has 639 nits target Y:
How to perform manual measurements for 21-Point Grayscale for specific nit level?
If you want to limit the displayed patches to 750 nits, find the closer 8-bit digital code value using the arrow keys, the 174 (756 nits), see the animated PNG:
Go again to the ColourSpace ''Settings'' and enable 'Limit Range' 174.
Go to 'Manual Measure window:
Define the steps you want, for example, 21-Point.
Move the RGB sliders at the lowest position (16.16.16).
Press to measure; it will measure black.
You can select the next patch using a left mouse click at the area with the red dot.
You can select the next/previous point using single left mouse clicks at the area above/below the three sliders.
How to perform HDR10 21-Point Grayscale sweep using a patchlist for specific nit levels?
Using the ''Limit Range'' function of ColourSpace, I have created 15 HDR10 patchlists for 21-Point Grayscale.
ColourSpace users can load any of those patchlists to measure 21-Point HDR10 Grayscale with a limit to the nits they want.
It will not require to enable Limit Range.
Select the ST.2048 REC.2020 as target colorspace, keep the Limit range unticked, select LEGAL patchscale for PGenerator users (or other pattern generator users with video level output) @ ColourSpace Settings.
Add metadata using HDFury GUI to the HD Fury Device you have connected at the output of PGenerator or use LG 2020/2021 HDMI Override menu to force/setup HDR10 metadata details.
Use the Manual Measure Window and load each patchset; I have posted picture examples about how to load a patchlist in this post's ''instructions'' area.
HDR10 21-Point Grayscale Patchlist Download Link
You can download the ZIP with 15 HDR10 21-Point Grayscale Patchsets here.