# UHD SDR calibration?



## glaufman (Nov 25, 2007)

Hi all... Been gone a while... Hope all is well...
I'm familiar with video calibration at 1080... A friend has asked me to do a new set, 4k, and I figured I'd just get the latest test patterns and go, but it seems technology has passed me by... I've been reading up, but it seems I'm missing something, so I hope you can all set me straight...

I see plenty of patterns available to"check" 4k HDR, but it seems people recommend not tweaking brightness, contrast, color and time in that mode, only grayscale... If that's so, I'm fine with it... For now...

But what about 4k SDR mode? Only patterns I can find available are Spears and munsel... That disc is on its way, but why not much talk about doing this, what an I missing?

Also, one of his two uses are cable through HDMI ( no 4k there, but also no disc player to use my old patterns)... If I put pattern files on USB, will this be usable for a proper Cal?

Lastly he also watches Netflix via built in widget.. I know Netflix offers a pattern, but it's less than ideal... So how does one calibrate this?


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## Jestered (Apr 15, 2018)

You didn't mention how you're attempting to calibrate, or have calibrated in the past. By the sounds of it I'm guessing you have a colorimeter and are using one of the popular calibration software packages. Since you're obtaining your own test patterns I'm also guessing you might be using HCFR. Anyway...

If you're using the method mentioned above, there isn't a standard for HDR calibration, as you've read. 4K is resolution and doesn't change anything when it comes to calibration. HDR is what changes and there's no standard for that (yet). So:

Calibrating 4K HDR - Leave the TV set to it's default settings until a proper way of calibrating is available.
Calibrating 4K SDR - This is exactly the same as calibrating 1080 SDR. Use the same equipment, test patterns and software to do this. It's literally no different than calibrating a 1080HD TV.


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## glaufman (Nov 25, 2007)

Thanks for the response... Yes, I've done a few calibrations before... yes, I use hcfr, even built one of their colorimeters, even though I don't use it due to the profiling... In the old days we had to Cal different res separately ... I guess maybe my memory is shot and that was more an analog vs digital thing... so today we trust the mfrs to upscale without messing with the range etc? And even if we didn't they don't have different settings when it's in upscale mode vs receiving an input that matches native res?

I've confirmed on the set that the settings are different in the HDMI input and the web widgets like Netflix... Any ideas on how to calibrate those widgets? 

I'd be willing to invest in an inexpensive test pattern generator, but just can't justify for my purposes just can't justify the price of either the video forge or even dvdo avlab... I see cheap stuff out there but I don't trust anything I don't see discussed here or my other favorite av forum... Any ideas?


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## Jestered (Apr 15, 2018)

glaufman said:


> Thanks for the response... Yes, I've done a few calibrations before... yes, I use hcfr, even built one of their colorimeters, even though I don't use it due to the profiling... In the old days we had to Cal different res separately ... I guess maybe my memory is shot and that was more an analog vs digital thing... so today we trust the mfrs to upscale without messing with the range etc? And even if we didn't they don't have different settings when it's in upscale mode vs receiving an input that matches native res?


You must be thinking of CRT caiibration. I wasn't doing this type of thing back when CRT TVs were the norm, so I don't know. What I do know is that calibrating a digital SDR signal does not change based on resolution changes. For the most part you are measuring and adjusting gray scale and color. Neither of those change at all with a change in resolution. For example, a pure white test pattern at 50% luminance displays a pure white color at 50% luminance. It doesn't matter what resolution it's in or if it's upscaled or not. The test pattern is displaying the same color at the same luminance, regardless of resolution. And that's all you're really measuring with a colorimeter.



glaufman said:


> I've confirmed on the set that the settings are different in the HDMI input and the web widgets like Netflix... Any ideas on how to calibrate those widgets?


Being able to calibrate different inputs separately is a good thing. Unfortunately unless Netflix has some test patterns that can be displayed in the Netflix app, you can't really calibrate it. In that case you would use the same settings that you came up with when you calibrated the HDMI input. That should be much better than nothing. From there you can adjust by eye if you feel it needs it. I typically just use the same calibration settings from the HDMI source/input though.



glaufman said:


> I'd be willing to invest in an inexpensive test pattern generator, but just can't justify for my purposes just can't justify the price of either the video forge or even dvdo avlab... I see cheap stuff out there but I don't trust anything I don't see discussed here or my other favorite av forum... Any ideas?


If you already know how to use HCFR, there's really no need to get a pattern generator unless you plan on doing this professionally or something. a few times for personal use is not worth it in my opinion. I've calibrated my last 6 or so TV's, including my current OLED, using HCFR and the free test patterns and will continue to use those tools.


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## glaufman (Nov 25, 2007)

My issue with using hcfr to generate the patterns is my video card send to be messing with the levels... There is a setting for that in hcfr but it didn't seem to change anything... At any rate, Netflix offers a test pattern but it's not as detailed as I like to work from... But I think my buddy has been able to take patterns and host on a webpage, so I'll give that a try... I know getting a generator isn't worth it, but if I thought I'd use it a few more times before it was obsolete I would treat myself...


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## Jestered (Apr 15, 2018)

glaufman said:


> My issue with using hcfr to generate the patterns is my video card send to be messing with the levels... There is a setting for that in hcfr but it didn't seem to change anything... At any rate, Netflix offers a test pattern but it's not as detailed as I like to work from... But I think my buddy has been able to take patterns and host on a webpage, so I'll give that a try... I know getting a generator isn't worth it, but if I thought I'd use it a few more times before it was obsolete I would treat myself...


I wouldn't use a computer or a webpage for the patterns. Computers use a different range than TV does. There are free test patterns you can download and burn to a dvd. This is what most people use with HCFR, including myself. Then you just run the test patterns/colors over HDMI using a bluray or DVD player. If you use a webpage you will be calibrating the wrong range for tv.

Do a Google search for "AVS HD 709 - Blu-ray & MP4 Calibration" to find the free patterns. Then just burn it to disk and use it that way.


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