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Rec. 709

ISF Calibration Photos

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23 hours ago, Tweaky said:

If you go back to page 6 of this thread and read my post from August 12, which is basically the same question, but a bit more technical, you can read REC 709's reply directly after it on August 16

if you look at Tonys posts above will see the HDR10 uhd test patterns from ray masciola, i too use these to setup my jvc for HDR nd have the same uhd disc it comes on. you can also down load the patterns for a charge from ray's site.

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Actually, since I've recently bought a 4K HDR TV [which still hasn't been delivered :( ] , I've been reading up on the calibration process at Rec 2020 reference gamut.

To say there is confusion about the process, and about the standard itself, would be a understatement.

And I'm not talking about just end users, I'm taking about seasoned ISF techs, and the guys that write the calibration software.

This basically all boils down to the High range of calibration in the 70% - 100%, where the HDR High Brightness starts kicking in.

 

Seems the start of the problem is the lack of standardization of just how many nits any particular movie is mastered to, be it for commercial release, or for transfer to UHD Bluray disc, some are mastered to 1000 nits, others 4000, and reference White for the HDR-10 spec is 10,000 nits.

No consumer visual playback device can output 4000, nits, and there is no display on the planet that can do 10,000 nit's, so the whole spec is ridiculous.

So what displays are doing to tame this brightness level so whatever the UHDR, is basically the same as a Iris of a projector, by stopping down to gradually reducing this high brightness to a reproducible level, this is being called Tone Mapping, and how hard it kicks in, at what range, for how long is all up to the individual manufacturer, th's why some UHDR TV's appear brighter than others.

This Tone Mapping switching in and out also effects the way any meter used for calibration reads the scene, and is compounded by the calibration software not knowing the ultimate brightness [Nit's ] level the display it is trying to calibrate, can go.

 

It seems they are working on it, or at least the guys writing the calibration software are discussing what can be done to at least help lessen the problem.

You can read what's going on at the AVS forum > Display Calibration > The Offical ChromaPure 3 thread.

 

To put the problem into some perspective, here is a post [#1244] I've copied and pasted from that thread, by Tom Huffman on the 19th Oct, who writes the software for ChromaPure calibration software.

 

Let me tell you a story.

When HDR was first introduced and I got the formula working, I realized right away that I really don't know how to implement it. The problem is that--unlike other gamma standards that define output at every video level by reference to 100% white, which is unspecified--HDR10 specified 100% white as 10,000 nits. No display can come even close to this. The OLEDs don't even reach 1/10 of this. Projectors are doing well if they reach 1% of this! As I had done before I reached out to a few industry insiders asking how this seemingly impossible standard was supposed to be implemented in the real world. I didn't receive any answer to my queries. This was strange. I had asked questions like this in the past and always got some input, but this time nothing. The only advice I received was to calibrate the best you could and just clip signals above the display's capabilities, which in most cases is about 70% video. This is not an ideal solution, but it worked.

As time went on I begin to hear a lot about tone mapping. In short, this is an attempt to bend the PQ curve to minimize clipping. The thing is, there is no standard for tone mapping. Its implementation is left up to every vendor and manufacturer. There is another phrase for tone mapping. It is called "Making sh*t up." It then occurred to me that the reason no one had answered my earlier query is that NO ONE KNEW.

After speaking to some industry folks recently, I decided to experiment with tone mapping. Based on one suggestion, I tried a flat 2.4 power law gamma. This looked shockingly good. It is counterintuitive at first glance. I mean what is the point of high dynamic range if you are not using high dynamic range? However, if you look at what HDR is doing, almost all of the increase in dynamic range is at the high end. There is some increase at the low end, but it is fairly small. By using a power law gamma you now cover the entire luminance range of the display without clipping. Since the display is in HDR mode you can take advantage of whatever high-end luminance that the display offers, so you increase the dynamic range by 500-600%. The only downside I see is that the low end is considerably elevated from what the PQ curve suggests. For example, the PQ curve specifies 0.32 nits output @ 10% video. A 2.4 power law gamma specifies 2.39 nits @ 10% video assuming 100% video is 600 nits. I am also going to try a hybrid gamma of PQ up to 50% video and then 2.4 power law above that. Since there is no standard, I am free to try literally anything. I'll use whatever looks the best by eyeballing, and I'll offer several options to users to pick whatever they think looks best.

This will all be released in the next version along with auto-cal for the Radiance Pro.

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Well it's been a while!

 

Thought I would share some shots of a Sony 760 ES projector I recently calibrated for a client. Not a cheap projector by any means, but it produced some stunning images.

 

 

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20171207_154426.jpg

20171207_154428.jpg

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Some before and after photos of a Sony X8500E that I calibrated for a client. The first two shots were taken prior to calibration using the 'Standard' picture mode. The following two shots were taken after the television was calibrated. Please forgive the angles of some of the photos!

20180302_131821 Before.jpg

20180302_131823 Before.jpg

20180302_131454 After (4).jpg

20180302_131454 After (5).jpg

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Again, it's easy to see far more range between Dark and light with the calibrated shots, everything opens up once a good white balance is achieved.

 

I might do a new metering of my Panasonic on the weekend that I got back in NOV and calibrated in DEC to see if it has drifted much [I'm expecting it has, which is why I haven't posted before and after shots yet] it shouldn't need that much of a touch up...[He says hopefully]:winky:

 

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Posted (edited)

Anybody feel like a quick game of name the TV? Yes, I forgot to jot down the name of the display.  If that looks like your TV /lounge-room wall, please feel free to jump in and let me know!

 

As usual, the shots are taken from the Spears & Munsell 2.0, and this particular scene is a torture test for a lot of uncalibrated display. 

 

If the display is using too much sharpness/edge enhancement the whole tree looks like a mess. Although the photos don't tend to pick this up, they do show the difference in both colour reproduction and contrast both before and after calibration.

 

The first shot is before calibration, and the following shot is after calibration. 

 

Before 1.JPG

After 6.JPG

Edited by Rec. 709
re-arrange order of photos

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Geez, that is a world of difference. Goodness!

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OUCH!

From the before to after shots, I'm taking a educated guess and saying it's a Samsung.

No other TV's have that much Blue [and in this particular case, also CYAN colour cast].....although the very newest  Sony's with LG panels are starting to show the same trait, but still not to the same extent.

Also the brightness level is OTT on the pre calibrated shot.......this is the new norm with TV display units I see, especially bad with Samsungs.

 

I thought we HiFi guys had it bad with the Loudness wars with over compressed, overly high level loudly master music with no dynamic range, seems we are having the visual equivalent trying to be thrown at us as the 'New Norm' with over bright TV's.

 

Thankfully I see there might be some common sense, and some absolute standard to this madness before it gets out of hand, abet it being at a PC monitor level for a start, with Phillips releasing the  Philips Momentum 436M6 monitor, with DisplayHDR 1000 certification from the Video Electronics Standards Association (VESA).

 

Hopefully TV manufacturers will quickly follow suit.

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On 09/05/2018 at 8:58 PM, Tweaky said:

OUCH!

From the before to after shots, I'm taking a educated guess and saying it's a Samsung.

No other TV's have that much Blue [and in this particular case, also CYAN colour cast].....although the very newest  Sony's with LG panels are starting to show the same trait, but still not to the same extent.

Also the brightness level is OTT on the pre calibrated shot.......this is the new norm with TV display units I see, especially bad with Samsungs.

 

I thought we HiFi guys had it bad with the Loudness wars with over compressed, overly high level loudly master music with no dynamic range, seems we are having the visual equivalent trying to be thrown at us as the 'New Norm' with over bright TV's.

 

Thankfully I see there might be some common sense, and some absolute standard to this madness before it gets out of hand, abet it being at a PC monitor level for a start, with Phillips releasing the  Philips Momentum 436M6 monitor, with DisplayHDR 1000 certification from the Video Electronics Standards Association (VESA).

 

Hopefully TV manufacturers will quickly follow suit.

Hey Tweaky,

 

I think you nailed it with the loudness comparison.

 

This particular TV may have been a Sony either in Standard or Vivid. If I were to hazard a guess I imagine it would have been Vivid.

 

Some manufacturers are adding reasonably good picture modes, but there's always still the abundance of OTT picture modes.

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No screenshots of before/after calibration this time. Just some photos of a very cool home theatre I was recently working in. And yes... deeply engrossed in my work, Frankenstein did give me a start once or twice!

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20180509_103133.jpg

20180509_103026.jpg

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Some quick photos of a Samsung 75" Inch TV which I calibrated in store.

 

The first photo was taken prior to the calibration and the following photo was taken after the TV was calibrated. Sorry for the lousy angle of the photos, the colour difference between the two is however quite apparent.

Unfortunately, photos never do justice to the actual image after calibration, which often appears softer in the photo than it actually is, but they're better than nothing! You will know what I mean if you've ever tried taking a photo of your own TV.

 

Bet you can't guess the model no from the photo! 1f609.png;-)

Before.JPG

After.JPG

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Posted (edited)

Wow, un-claibrated they really look garish.....even the other TV's on the left showing the grass are suffering the same.

 

Strangely it looks like most of the colour problem is with the secondaries with these TV's prior to calibration judging by your photos, very Yellow with a strong Cyan cast, which is scewering the Red's, as seen in the bottom bush center screen, to Orange.

 

The Grey tracking doesn't look too bad pre calibration, there still seems like reasonable shadow detail in the tree branches, which is good to know if I ever get asked to calibrate one of these TV's, as that usually takes me the longest to get correct.

 

What Gamma did you calibrate to for standard HD? I'm guessing around 2.4, as it's a seems a bit darker than the 2.2 I usually calibrate to.

Edited by Tweaky

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Some shots of a JVC-X7500 projector which I calibrated for a customer. While the picture looked good prior to calibration, the colour balance was tilted strongly towards blue. The picture also didn't have anywhere near as much pop or punch to it.

After readjusting the image to fix some geometry errors and fill the screen, panel alignment was redone and the lens refocused.

After calibrating the basic user controls, the colour balanced was fixed with greyscale and CMS calibration. A custom gamma setting was then created to maximise the projector's contrast ratio and give the picture some more pop.

After calibration the image was sharper and more detailed. Colour reproduction was both natural and convincing. The image also took on an almost 3D like look, as a result of the custom gamma curve and the JVC X-7500's excellent black levels.

Customer was very happy and I left to start the process all over again on another JVC projector (X5900).35bf1518194e5429ea53d4bfdb1fb5e3.jpg7ab6ea56708cd1c088f5d5c0c0a5b196.jpge0121dca7884376dc17d8b77cc8d9b49.jpg

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I have the pleasure of getting my JVC X5900 calibrated by Tony (rec 709) yesterday in Melbourne. Tony was here for the hi fi show. So happy with the outcome with picture ‘popping’ out, natural colours, sharper images and easy to the eye. Tony developed two profiles for me, HD and HDR mode.

 

When I got my JVC couple of months ago, I was so disappointed with the picture quality (especially the over saturation of colours in original HDR mode) and it took me a while (researching the web including asking questions here on stereonet forum) to configure to the picture which is was acceptable to me, pre calibration. But I was not wowed by the jvc until yesterday. Please invest in calibration if you have a jvc like me, but have no clue how to calibrate. The end result pictures paint a thousand words. 

 

Thanks Tony!

Edited by kc01

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