Originally Posted by rbronco21
I've read the same thing about WtW. I am kinda alarmed I have to max Contrast to get it below max white. Is that a cause for concern? Will it cause an issue as I get into more in-depth calibration? Do you prefer to see everything above 235, or is there some compromise?
You can see some graphs there about what each control of these are checking: https://www.avsforum.com/forum/139-d...l#post58776446
You can see why you need to leave 'headroom' there
, with some picture examples of 'out of video legal range values' using 'Mission Impossible - Fallout Blu-Ray' movie as example there
The 'standards' we have recommend to not clip but to allow headroom:
Locale to that page the info related with ''Grade-1 SDR Reference Monitor/TV Calibration Targets
According to EBU TECH 3320, 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 (235 @ 8-bit) , 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 (254 @ 8-bit) 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'.
There some cases where you can clip and not allow WTW, for example when you have an old Plasma which can't output 100 nits, (the Contrast slider @ Plasma control the light output), so you can clip for getting some more output (to reach 100 nits for example, so this will increase your contrast).
Other case is when you have an old projector or a projector with a reduced-output-from-usage lamp, and you can't reach for example 48 nits output, you can clip WTW to get some nits more, until you will get a new lamp.
These 2 examples are some tricks to get some more output from older devices.
Now modern displays can output at least 300-400 nits, and projector are bright enough to reach the peak output recommendations.
When you using your Contrast slider, if you reduce a lot more than its required, then you compress your signal, so you have to be careful.
The last bar have to slightly be flashing, it can happen for this to be visible when you will go close to your screen only, as its one 8-bit difference (background is 254 level, last flashing bar is 253), if you reduce a lot your contrast, it may be more visible the difference but this will compress your signal.
There another way to check your contrast setting if you have meter/software, to take measurements using 100-109% patterns, my calibration disk has such chapters to use with CalMAN for example (called Dynamic Range Clipping chapters) ot check your gamma also with changes of contrast values to the 100-109% levels.
If you have CalMAN see there