What does Display Certification actually mean?

Many of today's TVs and monitors offer a level of colour guarantee through the use of Certification or Validation

But what do such certification and validation programs actually mean, and what level of colour fidelity are they really guaranteeing?


Certification & Validation?

Display Certification

Display certification & verification certainly appears to promises a lot.

If we look at a Technicolor Certification press release we are promised the following:

While high-end devices continue to bring more power and speed, colour accuracy and consistency is sometimes slighted. Technicolor is helping solve this problem because great colour leads to great experiences. Colour is key to making sure users are getting the best online viewing experience possible...

As well as:

By being Technicolor Colour Certified, the - display - meets the same strict standards used in Hollywood and throughout the media and entertainment industry...

And from Calman we have:

Enabled through its close collaboration with Portrait Displays, the Verified by Calman program ensures each display is accurate out-of-the-box and true to multiple industry-standard colour gamuts.

As well as:

In the Verified by Calman program, displays are rigorously tested in the Portrait Displays colour lab to determine each display's performance. Only those displays that meet the program's stringent specifications for colour accuracy are awarded the Verified by Calman accreditation.

And from THX we have:

Colour Accuracy - We test to ensure all display images that are accurate to the original source, and all primary and blended colors are reproduced exactly as they were in the studio.

And from Pantone:

'Pantone Validated' brings their colour standards to electronic devices. Computer monitors, high definition televisions and projectors are judged by how well they reproduce the Pantone Matching Colours, or PMS requirements. Professionals who consider colour fidelity a mission-critical component in displays or output devices seek models evaluated and approved by Pantone, and that are identified by the Pantone Validated logo.

But what does this all mean in reality?

Colour accuracy is an attempting to certify a given display's ability to show the exact colour or greyscale level as defined by the signal sent to the display, based on the expected colour space's gamut and gamma specification.

This means, for example, that a give shade of Red is true to the defined red colour, and is not 'more of an orange' colour.


Certification and the reality

The big issue here is what 'standards' the certification programs aims to match, and more importantly to what level of accuracy?

Most of the 'certification/verification programs do not actually provide such information, leaving the user to guess at the level of guaranteed accuracy.

However, Portrait did provide information on the Technicolor/Calman certification, and it made for interesting reading.

Portrait's Technicolor Certification

Colour Gamut

Red = X 0.64, Y 0.33
Green = X 0.3, Y 0.6
Blue = X 0.15, Y 0.6

Acceptable variation <7 delta E

White Point

D65/6505 degrees K

Acceptable variation ± 10%

Grey Scale Balance

Acceptable variation <7 delta E

Gamma

Gamma = 2.2

Acceptable variation ± 0.1

The documentation also defined what this specification would mean in reality


Meeting the specification

Measured Green value not exact but within dE <7 target
Display meets spec
Typical viewer will be very pleased viewing this colour gamut

Display Certification

As can be seen, the acceptable variation of <7 dE is nothing like accurate enough for those looking for true calibration accuracy, where the maximum target deviation is <2.3 dE, which is the common accepted JND (Just Noticeable Difference) threshold, and more often <1 dE, as it is widely known that <2.3 dE is not the JND threshold for many colours.

THX Certification appears to have a tighter tolerance, as although they do not officially release their parameters some are known, with Red, Blue, Cyan, Magenta, and Yellow having an acceptable colour coordinate tolerance of ±0.005 xy, and Green having an acceptable tolerance of ±0.010 xy.

But, it is this lack of transparency on what is deemed as an acceptable tolerance, and what actual specifications are in use with any Certification or Validation, that is the key issue for those looking for accuracy guarantees

In simple terms, there are no guarantees!

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