Originally Posted by Toto84
For calibration for the dark mode would you stick to 100 nits as reference or higher?
These info below will be available to the upcoming LG guide for OLED I will upload to my site soon:
Grade-1 SDR Reference Monitor/TV Calibration Targets
The viewing of accurate images depends on an accurate calibration of the display, control over the viewing environment (lightning and room decor), as well as the appropriate placement of the observer relative to the screen.
The Reference Viewing Environment can be considered one where color critical decisions are made, while the Home Viewing Environment is where finalized deliverables are viewed, with the intent to best match the original artistic intent, as defined by the director and colorist within the Reference Viewing Environment.
The goad of home TV calibration is the Home Viewing Environment to match the Reference Viewing Environment image.
Within the professional industries reference monitors (Grade-1) are the standard for color critical work.
BU TECH 3320 (Version 4.1 - September 2019) - User Requirements for Video Monitors in Television Production, defines the technical characteristics for video broadcast monitors used in a professional TV production environment for evaluation and control of the images being produced.
Its describing the definition of Grade-1 SDR Reference Monitor with Standard Dynamic Range capabilities.
Grade-1 Monitors are devices for high-grade technical quality evaluation of images at key points in a color grading production workflow.
They are used for critical evaluation during post-production.
As a minimum requirement, these monitors shall have the quality properties of the image system they are used to evaluate.
It is expected that all applied technologies are state-of-the-art at this level as the Grade 1 monitor is a 'measuring instrument' for visual evaluation of image quality.
Grade-1 SDR Reference Monitor should be been calibrated and capable to produce a reference luminance level of 100 cd/m2 (nits) for 100% White (235 level @ 8-bit) patch on the screen.
Automatic Brightness Limiter (ABL) functions shall not be used for Grade-1 SDR Reference Monitors, this means that the monitor need to be capable to display 100 cd/m2 with a full field 100% Reference White pattern also.
100% luminance on the screen corresponds to a 10-bit luma signal of digital level 940, and the black level corresponds to a 10-bit luma signal of digital level 64.
100% luminance on the screen is defined as the luminance of a luma signal of digital level 940, but levels 941 through 1019 should also be correctly displayed.
The highest value of 10-bit luma signal is digital level 1019. The luma level 1019 is called 'Super-White' or '109% White'.
For the luminance gamma characteristic (Electro-Optical Transfer Function) of the screen, its recommended that a nominal value of 2.4 gamma to be used.
LG OLED Panel Auto Brightness Limiting (ABL)
But there is an ABL (Auto Brightness Limiter) present at all LG OLED TV's for the purpose of preventing them to consume too much power when displaying content with preponderance of bright elements, and protecting internal components from overheating.
The impact of the ABL, however, is limited to high-APL content such as hockey and winter sports during which can be observed a brightness reduction as the APL increases.
APL is the average level brightness (Luma) of the total numbers of pixel of an video image frame; defined as a percentage of the range between blanking and reference white level.
The LG 2018/2019 OLED TV's are able to reach about 150 cd/m2 on 100% APL using when you will take measurement using an 100% White full field pattern, so there is still some brightness headroom even for high-APL scenes because SDR content is mastered to a 100 cd/m2.
For reference level SDR movie playback for home; for being considered as 'Grade-1'; the TV should display calibrated colors with the color primaries (REC.709 color gamut) and reference white (D65), as specified in the relevant SDR video standard ITU-R BT.709-6 (Parameter values for the HDTV standards for production and international programme exchange - June 2015).