Clarity Calibration Posted July 29, 2017 Author Posted July 29, 2017 Things start to get a bit trickier at the low end, so take take your time. It sounds like what you're seeing is probably the content. Just watch your brightness and gamma, particulary the effect they have on each other. You're welcome, let me know how you get on. Sent from my SM-G935F using Tapatalk
srey Posted July 30, 2017 Posted July 30, 2017 I had a go at the calibration this arvo and i think it went pretty well. In fact the greyscale wasn't out by much on the factory settings, just a noticable bump in green/blue around 50-80% grey. Gamma was well out though, luminnace a fair bit too low all the way from 10% to 80%. Actually that's probably the only thing that worries me a bit; to get anywhere near the appropriate luminance I had to push the gamma gain for 20 and 30% stimulus all the way to the end of the scale (+50). It's pulled the curves back into shape, but I'm not sure if it's a safe thing to do?
Clarity Calibration Posted August 1, 2017 Author Posted August 1, 2017 I wouldn't worry too much about having to use the full range of luminance adjustment at the low end. I haven't done a VT60 in a while, but IIRC they did need a bit of a heavier hand at the low end. What could account for this is the gamma you started from, did you use 2.0 or 2.2 to adjust from? I would be more concerned with the +green error at 10%. If you have to settle for an error at 10% try to have it +blue, is this is far less noticeable than a +green error. As there's also a fair bit of luminance in the green channel, I suspect you may be able to ease back with the gamma adjustment at 10% if you can eliminate the green error.
srey Posted August 6, 2017 Posted August 6, 2017 On 01/08/2017 at 2:31 PM, Rec. 709 said: I wouldn't worry too much about having to use the full range of luminance adjustment at the low end. I haven't done a VT60 in a while, but IIRC they did need a bit of a heavier hand at the low end. What could account for this is the gamma you started from, did you use 2.0 or 2.2 to adjust from? I would be more concerned with the +green error at 10%. If you have to settle for an error at 10% try to have it +blue, is this is far less noticeable than a +green error. As there's also a fair bit of luminance in the green channel, I suspect you may be able to ease back with the gamma adjustment at 10% if you can eliminate the green error. Definitely set to 2.2, I am using the low panel setting though, maybe that has something to do with it. I brought the meter back from the office over the weekend and just had another go at the TV. Think I managed to improve on the white balance, although it is still out at 10%, but I took your advice and erred on the side of blue there. Gamma's still a bit bumpy but overall I'm pretty happy with the results. Thanks again for the help!
proftournesol Posted August 6, 2017 Posted August 6, 2017 Any idea how I can get a proper calibration of my LG OLED done outside a main city? North East Victoria for instance?
Clarity Calibration Posted August 7, 2017 Author Posted August 7, 2017 Although it's hard to see the exact readings from the graph, it doesn't look like it's out by much and may not actually be a visible error. I think you did a great job srey! :-) Side panel luminance may account for the differing gamma values, I was targeting BT1886 with the last VT60's I did, which is slightly different again. Based on what I can see from the graphs, gamma (EOTF) isn't too bad at all. I think it's time for you to enjoy some movies and appreciate your handy- work! :-)
Clarity Calibration Posted August 7, 2017 Author Posted August 7, 2017 proftournesol: I don't know if I can help, but if you want to shoot me a PM with some more details I will ask around.
Tweaky Posted August 12, 2017 Posted August 12, 2017 I've just updated my ChromaPure calibration software from V 2 to V3.1.6 which looks like a Big upgrade that now allows HDR calibration, plus the whole UI has had a big overhaul for the better. I'd previously watch a small video by ChromaPure showing the basics of HDR calibration [Please watch video to understand the question], but it seemed rather odd to me, as the way they went about it was to start at the 65% or 70% level, then work their way down to 5% or 10%, leaving everything above 70% seemingly uncalibrated. http://www.chromapure.com/movies/hdr/hdr.html Not yet having tried calibrating a HDR TV or PJ, I thought I'd better read up on what the differences might be over calibrating to standard HD 709, and came across this [below] at the ChromaPure site. I'd just wonder if this really is the correct way to go about it [omit calibrating above 70%] or am I missing something? HDR (High Dynamic Range) Gamma HDR gamma works very differently from all of the other gamma systems discussed above. HDR10—which is currently the dominant standard, though several others are waiting in the wings—assumes that 100% output is an absolute value of 10,000 cd/m2. This is unlike any other gamma system for which 100% is a relative value that changes depending upon the capabilities of the display. The absolute spec of 10,000 cd/m2 causes all sorts of problems for HDR10, not the least of which is that it becomes impossible to calibrate gamma above 60%-75% video input. Current displays are simply not capable of outputting 10,000 cd/m2, so all the user can do is measure and calibrate up to the maximum video level that HDR10 allows, and for current displays this is generally no more than 75%. Above that you just have to let the display clip. Some people talk about tone mapping, which would gradually roll off the response instead of abruptly clipping at the limit of the display’s ability. However, there is currently no standard for this. There are other HDR standards that are almost certainly superior to HDR10, but they have yet to gain much traction (All current UHD discs use HDR10). DolbyVision, which is one HDR approach that many tout as technically superior, requires a licensing fee and is thus at a competitive disadvantage to HDR10, which is open source. There are several points to keep in mind about gamma: The gamma of an HD display should be either a power law 2.22, sRGB, or BT.1886. BT.1886 is the preferred standard. The gamma of a UHD display showing UHD content should be HDR. The gamma of red, green, and blue, should all be the same. If they are different, then you will have a problem with grayscale tracking. In fact, grayscale tracking and RGB gamma are essentially the same. Do not use the contrast and brightness controls to affect gamma. Use a pluge pattern to set brightness and a white pluge along with white balance and total output measurements to set contrast. Because of gamma, 50% input does not produce a 50% output. To get 50% output, you need a signal input of between 70-80%. Conversely, with a typical display 50% input produces only about an 18% output. Getting gamma is important not only to achieve a balance between shadow detail and high contrast. A good gamma response will help to provide the image with great depth and realism.
Clarity Calibration Posted August 16, 2017 Author Posted August 16, 2017 HDR calibration is a little more tricky. The peak output of the display does not matter as much when you're using SDR gamma values (2.2, BT 1886 etc), whereas HDR gamma specifies a value of 1,000 nits. As of today, some displays can reproduce 1,000 nits, whereas others I still trying to catch up and projectors are nowhere near 1,000 nits. Through into the mix that some discs UHD are mastered at values exceeding 1,000 nits and things get even trickier. With this in mind, you want to let the display achieve it's peak light output at the top end. If you're dealing with a display that exceeds 1,000 nits there are still some very good reasons not to tame the top end. This is my take on why it's set this way. I have communicated with Tom Huffman a number of times and he's a very knowledgable guy, so you're in safe hands. :-)
Tweaky Posted August 17, 2017 Posted August 17, 2017 I'm reading this from the V3 software manual, I'm guessing this is what you mean on the way to proceed. C Select the Rec. 2020 reference gamut also in the Options module. Further, when using the Color Management module select 50% intensity and 50% saturation targets. Use special test patterns explicitly designed for HDR. Regular test patterns will not work properly In all other respects UHD calibration is no different than calibrating standard Blu‐ray or DVD sources.
Clarity Calibration Posted August 22, 2017 Author Posted August 22, 2017 On 17/08/2017 at 10:41 PM, Tweaky said: I'm reading this from the V3 software manual, I'm guessing this is what you mean on the way to proceed. C Select the Rec. 2020 reference gamut also in the Options module. Further, when using the Color Management module select 50% intensity and 50% saturation targets. Use special test patterns explicitly designed for HDR. Regular test patterns will not work properly In all other respects UHD calibration is no different than calibrating standard Blu‐ray or DVD sources. Bwah! Missed this one, sorry Tweaky. Yes, that's correct, Home Interface/Pre-Calibration Settings/ Options: work your way through setting the correct colour gamut, EOTF and then change to 50% in the CMS. Hope it goes well!
Clarity Calibration Posted August 22, 2017 Author Posted August 22, 2017 Some photos of a home theatre I recently calibrated, with some seriously nice gear!
Tweaky Posted August 23, 2017 Posted August 23, 2017 (edited) Did you calibrate the surround system as well? or just the visuals ? Sort of a strange option , well to me at least, opting for a 18% Grey wall colour if the room is light controlled [Judging by the ceiling lighting and aircon vent, it is].....the owner isn't in Graphic grading or post production are they, just a guess, as it would seem the logical choice for somebody doing that sort of job. I also see it's a curved screen....interesting. I see V3 ChromaPure now has a 15 zone screen uniformity test pattern, what a sadistic thing to include [ ] , and you would have to be a masochist to use it, being there is no way of making any adjustments for any of the individual zones of the screen you are metering. But in saying that.....did you happen to run that particular test of a curved screen yet....it would be interesting if having a curved screen on a TV works as well to counteract the edge light fall-off that old 3 lens CRT PJ's used to suffer, and that was the main reason for there use. Also IMHO I think ChromaPure needs to update the manual a bit more often to represent the gradual changes with the software updates, the current V3 manual available represents the BIG change when V3 came out, which was 30/12/2015, but there have been 16 updates since then [if including the current BETA ] , and regretfully, some things aren't as clear as they could be, especially to somebody new to the ChromaPure software see differences between what's mentioned in the manual, and what they experience during calibration with the latest version. To anybody else not directly involved with this conversation, but still interested in it's content, the Video Calibration For Dummies thread [A total A to Z walkthrough, in order, of the calibration process ] which I'll link to yet again, below, has now been updated to represent the changes in the user interface and software changes in ChromaPure V3, it also has a small section at the very end relating to calibration of HDR TV's / PJ's.....so read and enjoy. http://www.curtpalme.com/forum/viewtopic.php?t=35322 Edited August 23, 2017 by Tweaky
Clarity Calibration Posted September 4, 2017 Author Posted September 4, 2017 Did you calibrate the surround system as well? or just the visuals ? Sort of a strange option , well to me at least, opting for a 18% Grey wall colour if the room is light controlled [Judging by the ceiling lighting and aircon vent, it is].....the owner isn't in Graphic grading or post production are they, just a guess, as it would seem the logical choice for somebody doing that sort of job. I also see it's a curved screen....interesting. I see V3 ChromaPure now has a 15 zone screen uniformity test pattern, what a sadistic thing to include [ [emoji6] ] , and you would have to be a masochist to use it, being there is no way of making any adjustments for any of the individual zones of the screen you are metering. But in saying that.....did you happen to run that particular test of a curved screen yet....it would be interesting if having a curved screen on a TV works as well to counteract the edge light fall-off that old 3 lens CRT PJ's used to suffer, and that was the main reason for there use. Also IMHO I think ChromaPure needs to update the manual a bit more often to represent the gradual changes with the software updates, the current V3 manual available represents the BIG change when V3 came out, which was 30/12/2015, but there have been 16 updates since then [if including the current BETA ] , and regretfully, some things aren't as clear as they could be, especially to somebody new to the ChromaPure software see differences between what's mentioned in the manual, and what they experience during calibration with the latest version. To anybody else not directly involved with this conversation, but still interested in it's content, the Video Calibration For Dummies thread [A total A to Z walkthrough, in order, of the calibration process ] which I'll link to yet again, below, has now been updated to represent the changes in the user interface and software changes in ChromaPure V3, it also has a small section at the very end relating to calibration of HDR TV's / PJ's.....so read and enjoy. http://www.curtpalme.com/forum/viewtopic.php?t=35322 hehe... I agree whole heartedly! It's a great tool for reviewing screens, but there are some other ways you can test screen uniformity quickly in the field to see if they are going to impact your measurements. I calibrated this one a little while back (for video only) and I'm pretty sure it was a flat screen. I think it's the shape of the bezel which may make it looked a little curved. I must admit I was a little surprised by the colour of the wall as well. It's not common to see this type of colour tone outside of a grading environment. Having said that, there are some very good reasons to use a neutral grey wall behind a flat panel TV (not a projector). The wall colour is going to affect your overall perception of colour, particularly if you're using bias lighting, which I usually recommend to my clients. I played around a bit with using colour on the wall behind my65" Panasonic VT30 a few years back. I finally settled on a Neutral grey with D65 back lighting. If you're interested, I still have the paint formula around somewhere.
mikezilla2 Posted September 5, 2017 Posted September 5, 2017 there a Point if i cant afford a calbarater / game alot ?
Tweaky Posted September 7, 2017 Posted September 7, 2017 On 9/6/2017 at 0:10 AM, mikezilla2 said: there a Point if i cant afford a calbarater / game alot ? What is your question, if it is a question ? Your reply doesn't seem to make sense, is it voiced opinion on the thread generally? , or are you asking if it's worth getting your own calibration meter and software and doing it yourself? If it's the last part, well if owing a Projector, it's 100% worth owning your own metering gear, as the PJ's lamps change output of time used.....TV's , certainly worth having them calibrated, the difference is BIG on most TV's, but depends on usage [ If gaming you will tend to be a heavy TV user, and the screen will show a colour cast over time], you can adjust for that it you have your own metering. I don't know 100%, but I suspect 4K UHD or HDR displays will have a performance hit a lot bigger over time than current standard 1080p HD TV's have. if only due to the light output [NIT's] they might be asked to display if playing back 4K material, and how often that is asked of them. Nobody knows, it's a Grey area......Personally, I wouldn't buy a HDR OLED screen ATM....it's big $$$ asked for YOU to test this stuff
Clarity Calibration Posted September 19, 2017 Author Posted September 19, 2017 Some photos of a JVC X7500 that I recently calibrated for a client and member of StereoNet 1
Tweaky Posted September 19, 2017 Posted September 19, 2017 Did you have to make two presets? One for HDR 4k playback, and another for standard Bluray? Reason I ask is that this is the replacement model PJ I'm looking at getting [Unless JVC brings out a newer model to counteract Sony's newer models]
betty boop Posted September 19, 2017 Posted September 19, 2017 1 minute ago, Tweaky said: Did you have to make two presets? One for HDR 4k playback, and another for standard Bluray? Reason I ask is that this is the replacement model PJ I'm looking at getting [Unless JVC brings out a newer model to counteract Sony's newer models] you'd have to. requirement for blu-ray and uhd are poles apart. the 7500 has been superceded by the 7900. again little tinker, minor update like previous. prob x8000? to follow next year might be more major.
Tweaky Posted September 19, 2017 Posted September 19, 2017 Requirements might be poles apart, but measurements aren't that different when going through the process. As in 'More Major update ' of the JVC's....full 4K rather than pixel shifting?
betty boop Posted September 19, 2017 Posted September 19, 2017 19 minutes ago, Tweaky said: Requirements might be poles apart, but measurements aren't that different when going through the process. As in 'More Major update ' of the JVC's....full 4K rather than pixel shifting? they need different presents, you cant run the same for both formats, not to take tony's thread offline. below is link to new release. if you want native 4k jvc has had the z1 at $1 under $40k for quite a few months now,
betty boop Posted September 19, 2017 Posted September 19, 2017 9 hours ago, Rec. 709 said: Some photos of a JVC X7500 that I recently calibrated for a client and member of StereoNet tony looks like great result there how did it go for blu-ray and uhd
DBM Posted September 20, 2017 Posted September 20, 2017 Not sure, but may be my room Al..if so, have watched quite a few bluray & uhd since Tony calibrated the PJ. Some bluray discs I already had, have been watched again, and they have never looked better. UHD is stunning, I'm even enjoying movies I didn't think were that good as a movie. A big thanks to Tony, and to Simon at VAF for recommending Tony. For me with no calibration equipement or knowledge, and spending upwards of 6k on a PJ, getting someone with Tony's skills to get max performance was a no brainer. I wasn't disappointed. 2
betty boop Posted September 20, 2017 Posted September 20, 2017 6 hours ago, DBM said: Not sure, but may be my room Al..if so, have watched quite a few bluray & uhd since Tony calibrated the PJ. Some bluray discs I already had, have been watched again, and they have never looked better. UHD is stunning, I'm even enjoying movies I didn't think were that good as a movie. A big thanks to Tony, and to Simon at VAF for recommending Tony. For me with no calibration equipement or knowledge, and spending upwards of 6k on a PJ, getting someone with Tony's skills to get max performance was a no brainer. I wasn't disappointed. that is just fantastic to hear been enjoying both blu-ray and uhd side and all come together nicely audio and video. good to hear been well looked after to get you there
DBM Posted September 20, 2017 Posted September 20, 2017 Not quite there yet..HT sorted, now to up the 2 channel side ..this is a great site, but I think it has made me a bit nuts, and a lot poorer..
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