I'm calibrating a Samsung UN40ES6100 using HCFR and the AVSHD709 patterns. I use the basic patterns to adjust contrast and brightness before starting with the greyscale calibration. Calibrating the display at Warm2 and Movie mode.

The question I have is specifically with white clipping. On the white clipping pattern, I can set the contrast at 100 (probably not a good idea), and the values from 236 to 255 always flash quite noticeably. Is that an issue? Should I be compensating with white balance gain, or gamma?

I ended up with a calibration with flat colour temperature of 6500K and a flat 2.2 gamma. I think the tv is set to -2 gamma and I used white balance offsets and gains to turn the blues way down mostly, with some tweaks in 10p white balance. My white is 35 fL. Colour accuracy is good with the auto color space. The custom color space seemed to have incredibly low reds that I couldn't fix. So all-in all, the calibration went very well, except for that white clipping pattern.

I thought about adjusting the blue in the service menu, because I had to adjust blue way way down in both offset and gain, but I don't really want to get there. Is there some kind of contrast adjustment in the service menu that would fix this problem, if it's a real problem? Not sure I'd want to touch it.

Also, as an aside, I wanted to turn on the night/day cal modes in the service menu, and was comfortable doing that. Unfortunately when I turned them on, all of the display modes on my tv became way darker, so dark that with backlight at max and contrast at max, I was just barely able to get 35 fL for white. Turned the night/day cal modes off and everything returned to the way it was before.

Any help would be appreciated. Thanks.

There shouldn't be any issue if you leave contrast 100 - especially if you are not clipping through 255. I would run a color clipping pattern to make sure each individual channel is flashing above 235 at the least. Flashing through 255 just means you have extra headroom to work with.

Good idea. I think there's a colour clipping pattern in the additional patterns folder.

Hi Scott,

By looking the contrast pattern the purpose is not only to see them flashing, it's ideally the flashing bars to have a neutral/grayish shade, not with pink/red/green/blue-ish shade.

I have a spyder5 and just recently became aware of ArgyllCMS and HCFR, so I did the grey scale calibration (2 pt and then 10 pt white balance) to make sure RGB levels are correct for 6500K and my gamma is flat at 2.2.

So my greys should be neutral. Just curious why my tv was still showing the flashing pattern behind 236 - 255 on the white clipping test pattern when I already have contrast at max. Doesn't sound like it's a problem.

I could probably push the tv and drop the gamma one more notch for 2.3, but I'm pretty happy with flat 2.2. I don't think my tv is capable of something like BT. 1886 as I don't have a 10 point gamma control. I'm assuming that's what you'd need. The CMS control on this samsung has the weird controls where you adjust the red, green and blue for each colour. It doesn't have the lightness, hue, saturation, tint controls that I see described elsewhere. The custom colour space is too incorrect for me to adjust.

So I think as far as my tv goes, if the contrast and white clipping patter is fine as it is, then I probably have my tv as good as it's ever going to be.

If you are using computer with MadVR for watching movies (or in this case, AVSHD) and bars beyond 236 and below 16 are flashing you have your RGB level set wrong. And with RGB level I mean what some people call "HDMI black level". When they are correct MadVR should just flat out clip them out no matter where you have your contrast and brightness sliders set at. Make sure you have your RGB level set to full in your GPU control panel (and you have your TV HDMI black level match it) and in your MadVR properties make sure is set to send your display PC Levels 0-255. MadVR will do its magic and remove the garbage below 16 and above 235 (which movies never contain) and you wont reduce the picture quality for games which setting RGB levels to Limited will do, in theory.

Thanks for the reply. I'm using an Xbox One. Displaying the test patterns on my tv through a USB stick attached to the Xbox One. The Xbox is set to standard (16-235) and my tv is set to match. I can't remember what the Samsung setting is labelled (Normal?), but I know it's the right one.

Sorry, then i cant help much. Though out of curiosity have you tried setting both to Full? If Xbox is at all smart it should do the same as MadVR and clip them out. If it does i would leave it at that and set the contrast where 234 is barely visible. Some people think doing this will somehow reduce quality but I say they are being OCD over nothing, the conversion should be lossless in this day and age.

I've read a lot of things suggest the RGB output on Xbox One is messed up so it's best to leave it at standard (16-235) output, so I'd have to have my tv match.

I think I'm misunderstanding what you're asking me to do. Are you saying it's better to leave it at RGB and use my computer to watch movies, or are you suggesting there's a way to test whether my tv is actually set to 16-235 where i want it?

Wow, I may actually have my black level set wrong. I'm going to check when I get home. Looking at the calibration settings in this review for that ES6100 line, it's set to hdmi black level "low." I believe mine is set at the other option. Guess I have some work to do again tonight if it's set wrong.

https://reviews.lcdtvbuyingguide.com...esettings.html

As pointed out by others, being able to see flashing beyond 236 is not a problem, especially if your Contrast setting is already at 100%. The white calibration patterns are used to ensure that clipping, if any, does not occur below 235.

Double checked my input setting on my tv and it's set to low, which is consistent with review calibrations, so I'm confident it's correct. Seems like everything is as it should be then. Thanks for all the help.

Two other possible issues: One is if you are indeed adjusting to 6500K instead of D65. Because the Kelvins number doesn't take into account the blue component, 6500K can range from a greenish to a magenta tint. Michael Chen (MichaelTLV) demonstrated this in photographs years ago. You should be aiming for D65, which is a specific location (x 0.3127, y 0.3290) on the CIE chart. Second, the Spyder series of meters aren't all that great in terms of accuracy or repeatability, with high reported meter-to-meter variance. You might have a good one, but the odds are probably against it.

Unfortunately the CMS controls and custom colour space on my tv seem to be junk. But grey across the range and at white appear to be neutral, so I'm pretty confident in the accuracy of the meter (good enough for me). I've gone back and verified my calibration, and it measured out the same way. Don't think there's much I can do about adjusting for D65, but I doubt that's the reason for the white clipping pattern displaying the way it does.

In HCFR, if you use the default colour space (REC 709) then the white point is D65 (not just 6500K).

That's the colour space I have it set to, so then I guess it should be correct.

Yes, since in HCFR you are adjusting R/G/B to achieve D65 (x=0.3127, y=0.3290). Some programs may use the term "6500K" loosely, but all programs use the same white point for REC 709.

I don't have or use HCFR, so am not familiar with its conventions. Some folks here have used "6500K" and "D65" interchangeably in the past, and as you are aware, they aren't. I just wanted to point out that there are other possibilities.

If he is able to see bar 235 and above and he is unable to calibrate them out that means he will never see pure whites in movies. All white things will be the same dirty grey color as the flashing 235 bar at max. Contrast ratio is dramatically reduced as a result. When everything is correcty set for movie watching bar 235 and above should be pure white and invisible from the background.

No no no. I meant try setting your Xbox and TV to full 0-255 PC RGB levels and then see what your AVSHD clipping patterns looks like. Ideally XBox should then convert the movie 16-235 signal to 0-255 and clip out everything above 235 and below 16, make them invisible as they should be.

Again, this is what should happen ideally. Unless xbox really does screw up with rgb.

*Edit* Alternatively you could try Ycbcr mode if your xbox has one, this takes the whole HDMI black level out of the equation and grey it out. The result should be the same, bars below 16 and above 235 clipped.

That's not true in most cases.

Let's say you calibrate two TVs both to 35 fL at level 235, and let's say TV1 clips at 235 while TV2 continues to respond above 235.

The whites will look identical on TV2 and TV1; one won't look any more "dirty grey" than the other. The difference between the two, is that when there is any WTW ("white-than-white") such as specular highlights, TV2 will be able to show that being brighter than white, whereas TV1 will show WTW the same as white, so in a sense it will look more "grey".

The scenario that you described would only arise if the TV needs to run "flat out" at maximum brightness, in which case reserving some heading will lead to a drop in brightness at 100% white.

Is this an "issue" with many tvs? I took a look at standard mode yesterday because I'm trying to do a rough calibration for game mode, which forces standard. Can't say that's going well, but I expected it. It exhibits the same issue with the white clipping pattern, but that may because red starts to clip around 89 contrast on standard mode where the other colours do not. Doesn't seem like any mode on this tv will allow for a contrast high enough to use that white clipping pattern as expected.

I will say, I'm happy with the way it looks. The nerd in me always wants to try to maximize and improve everything like this, but if this is what I get I'm satisfied.

You know, I find the whole WTW and BTB thing puzzling. Because their supposed existence fights against everything I as a computer nerd know (or think I know, I'm always open to new ideas and fix the old) about the way SDR graphic are outputted (be it computer graphics or video. HDR is something completely new) and how digital displays work at their basic.

There are two RGB range formats, the legacy TV one (16-235) and PC one (0-255). They are both essentially the same, both have peak white and bottom black. Only difference is that the TV signal reaches its peak white at the 235 where PC reaches it at the 255. But side by side they are essentially the same, their reference whites are equally white and blacks are equally black. The TV one just has less steps between the two extremes which techically makes it more prone to banding but I digress...

Point is that for TV signal its maxed out at both 16 and 235, there is NOTHING beyond those and in any video file encoded in that format. How calibration discs get around that is that they are actually 0-255 video files but are flagged as 16-235 or so I believe. I have not actually opened the file and checked but that would make sense to me. So the information for above 235 and below 16 is there in the file but they should NOT be visible when everything in signal chain is correct for movie watching.

Actually if I am correct Bluray movies are encoded in Ycbcr which is hard limited to 16-235. Unlike with calibration disc above there simply is no data beyond that range, no specular highlights, nothing. You can pretty much test this out with your Bluray player. Set it in Ycbcr mode (which most bluray players should have). For bluray movies it sends the signal forward unaltered and lets the TV do the RGB conversion. But in case of calibration disc like AVSHD it actually converts it to Ycbcr and see what happens, or atleast with every Samsung TV that I have seen has happened? The information beyond 235 and 16 are hard clipped away. No matter how you tweak your TV brightness and contrast slider they are gone before it reaches your TV. I believe bars 235 and 16 are called "Reference White" and "Reference Black" for a reason.

So, in case of your TV comparison the way I see it is this: TV2 has its 235 reference white at 150 nits and say, 0.05 blacks resulting in 3000:1 contrast ratio and it peaks in WTW information at 170 nits (just threw the number out of my head for comparison) for 3400:1 contrast ratio. But it is expecting a signal that never arrives in real life content and therefore is limited to 3000:1 contrast ratio for every movie disc it shows. Where as the TV1 is IMHO correctly calibrated to push the 235 reference white to the same brightness as TV2 WTW peak white, and then have backlight turned down so the whites are at 150 nits but blacks are deepened as a result too. The TV1 shows the movie accurately, it shows all the black and white detail that really exists in the movie disc and yet has the panels capabilities maxed out on both black and white end, 3400:1 contrast ratio is preserved resulting in more punchier picture compared to TV2 and with no detail loss.



What am I missing or getting wrong here? Because no matter how I look at it with the information I have the whole BTB and WTW talk to me seems to me nothing more than someone once had their RGB range mismatched somewhere in the signal chain resulting in washed out picture, then he reduced the brightness slider to get his blacks black again at 16 and then calling the dirty whites that he cant get rid of as "having more detail" because the calibration disc says so but not really understanding what he is actually seeing.

Or maybe I am not understanding something? Help me out here.

IIRC, the 16-235 limit for YCbCr as it is encoded on disc is not a hard limit, but is termed a "legal" one. This means that info above 235 or under 16 can make its way onto the medium. You definitely shouldn't see the below-16 info, but, sometimes, not taking into account the above-235 data when doing white balance can lead to some weird artifacts (magenta or greenish highlights in welding flare, etc.) when it pops up. I guess it just depends on the display.

The issue of "preserving WTW" has been debated for years, but that was NOT the point I was making.
However, you may want to see what EBU TECH 3320 ("USER REQUIREMENTS FOR VIDEO MONITORS IN TELEVISION PRODUCTION, VERSION 3.0" Section 5.1, Note 2) has to say on this. It specifically states that

I am NOT advocating lowering the contrast in order to see WTW. I was simply pointing out that, if the TV is already set to 100% contrast and you're getting the desired ftL, even if you can still see flashing beyond 235 it does not make the white "dirty grey" as you claimed.

Well, I am firmly in a camp that thinks that in video signal the WTW and BTB data is garbage and should not exist just like there is no data above 255 and below 0 in PC levels. If nothing else then to avoid possible artifacts that may have creeped in the video that technically are not even part of the movie, things Rolls-Royce mentioned.


And to figure out what problems Scott has, if its really just WTW he is seeing or if he has a RGB mismatch which I believe, Scott_Arms when you calibrated your brightness with Black clipping patterd did you have to reduce your brightness slider a noticeable amount below 45 to make bar Reference Black 16 not flash? Because if you did you definetly have a RGB range mismatch. Brightness of 45 in Samsung TV's is the level (or very near it, the exact point is easy to determine with HCFR and continous black measurement) where it neither artificially elevates the black level nor hard clip it away and it does not matter if its being fed RGB Limited or RGB Full or Ycbcr signal, that point does not change. You should not need to touch that setting most of the time. If you did then you are basically bruteforcing the blacks down to match the video levels but as a result you are also causing a severe black crush for the videogames.

If the 16 and below are invisible at 45 brightness but whites above 235 are still visible then yeah maybe you really are just seeing WTW data, a matter will not touch again until I have more information.

Not at home right now, but from memory my contrast is 100 and my brightness is either set at 44 or 45. I'd have to check the backlight, but I think it's at 12. And my tv is in movie mode.

In that case maybe it really is WTW. Because RGB range will always affect both ends when they are mismatched, either by washing out the picture or by crushing all the details from both ends depending on which way around they are set wrong.

This is right out of the AVS HD 709 patterns manual section on the white clipping pattern.

"Some displays will show all the bars even on their highest
setting. If your electronics still show all the bars at maximum,
then clipping is good with the highest setting."

I'm curious to know how these patterns work. So if your contrast is too high, you'll see the white clip detrimentally and the upper range will start to become the same tint(?) because your tv is unable to display more red, green and blue. Once they've capped you can't make anything whiter. So I get that part. You lose distinction between shades in the upper range once you start clipping. But what is the drop shadow that flashes, and why does it disappear?

I'll post my full settings when I get home today, including white balance.

Another thing to note is to set my white fL or cd/m2 as I begin calibrating, I use the ColorHCFR window test patterns with the HCFR software. I use the 100-IRE white window pattern to set my fL for my given contrast and adjust backlight until I get my desired fL, which is approximately 35. I believe that's 120 cd/m2. It looks white, and not grey.