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Deinorius
Joined: 29 Aug 2011
Posts: 13
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 Link Posted: Tue Aug 30, 2011 2:43 pm Post subject: Calibration for LCD TV w/ LED Backlight - different method? |
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Hi
I started my own calibration with the help of the guide for dummies. I couldn't have been doing anything without it.
But I still have a few problems. It seems I'm not the only one. I've got a Samsung UE46D7000, it's a LCD LED TV, which got a seperate control for backlight brightness.
So, if I would want to adjust contrast or color with the Luminance, it can only fail. With AVSHD 709 contrast test picture it has to be 95 (now it seems to be the max 100, which is odd). If I set backlight too high... you get the picture.
What should I do, set backlight to minimum?
But that's not the only problem. My gamma is another. It starts high and becomes low. You'll see in my file. Maybe it's because of the contrast, but the gamma control only affects the wohle gamma. No idea how to manage that.
Then there's the color control. You write to set with red pattern 21 % of white pattern Luminance. Well I never get there, not even close. Even with lower contrast I have to set color to 100 where 50 is default.
With the CMS I can adjust every primary and secondary color nearly perfect, but deltaE is still too high with Red, Blue and Magenta because of the Luminance I assume.
What can you advise to me? Should I do the calibration with a lower backlight? The range of the TV is within 0-20 and I did it with 6 (138 cd/mē / 39-40 ftL with white pattern). Not much more to get more down.
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kal
Forum Administrator
Joined: 06 Mar 2006
Posts: 17860
Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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| Link Posted: Tue Aug 30, 2011 3:58 pm Post subject: |
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Every TV will behave differently and have different sets of controls including something like backlighting. I would play around with various levels of backlighting and see how it affects the calibration outcome.
| Deinorius wrote: | | But that's not the only problem. My gamma is another. It starts high and becomes low. You'll see in my file. Maybe it's because of the contrast, but the gamma control only affects the wohle gamma. No idea how to manage that. |
It may be simply how the TV is designed. If you want perfect gamma you may need to use an external video processor that lets you tweak gamma at various points from black to white (for example: http://www.curtpalme.com/Radiance.shtm).
| Quote: | | What can you advise to me? Should I do the calibration with a lower backlight? The range of the TV is within 0-20 and I did it with 6 (138 cd/mē / 39-40 ftL with white pattern). Not much more to get more down. |
Try it lower and see what happens. Every TV is different. Sometimes you need to play with the full range of controls just to get a sense of what they do. Play around with the controls, see how they interact.
Another thing to keep in mind is that it's usually impossible to get perfection on most displays. Usually some form of compromise has to to be made. For example, increased light output at the expense of proper greyscale tracking. You often have to pick and choose what compromises you're willing to live with.
If every TV was perfect or could be perfectly calibrated, most of the features found in video processors like the Radiance (see: http://www.curtpalme.com/Radiance.shtm) would not be needed.
Kal
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Deinorius
Joined: 29 Aug 2011
Posts: 13
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| Link Posted: Tue Aug 30, 2011 5:09 pm Post subject: |
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OK, then I'll do some try and error. A friend of mine bought a similar but bigger TV. Let's see, what that does.
About the gamma: Except for the gamma control, which just sets literally the average gamma, how do the other settings effect gamma itself.
When I look on my before gamma, the old curve just had a discrepancy of 0.22. Now it got a discrepancy of 0.65! Holy crap!
Maybe I can't get a perfect gamma curve, I can live with that. But it would be better to get that flat curve again with a nearly correct average gamma. You can see in my before file.
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kal
Forum Administrator
Joined: 06 Mar 2006
Posts: 17860
Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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| Link Posted: Tue Aug 30, 2011 5:21 pm Post subject: |
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| Deinorius wrote: | | About the gamma: Except for the gamma control, which just sets literally the average gamma, how do the other settings effect gamma itself. |
That would be a question only the manufacturer can answer as it depends on how the manufacturer implemented the display and controls and what sort of gamma control and curve they implement (if any at all).
Normally other controls shouldn't affect gamma but that's not how the real world works. Every display has a different curve either naturally or because the manufacturer forces it or because they give you tools to adjust it. Not all manufacturers give you the controls to tweak the curve at one point or even multiple points.
Kal
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Deinorius
Joined: 29 Aug 2011
Posts: 13
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| Link Posted: Tue Aug 30, 2011 5:28 pm Post subject: |
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A case for the service menu? ... just kidding.
But I'm still confused about the drastic change of the curve discrepancy.
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kal
Forum Administrator
Joined: 06 Mar 2006
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Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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| Link Posted: Tue Aug 30, 2011 5:58 pm Post subject: |
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Service menus may indeed give you more control/flexibility. Many people use them for their displays. Many manufacturers hide many of the controls you need for calibration in there as well as they don't want the average consumer messing things up.
The manufacturer is likely best positioned to explain why the gamma curve changes drastically when you make adjustments. You could also try asking other owners of the same set that have done calibration by themselves. Some of them may be able to offer input.
Kal
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Deinorius
Joined: 29 Aug 2011
Posts: 13
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| Link Posted: Tue Aug 30, 2011 6:25 pm Post subject: |
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OK, thanks for the answers. Maybe I can find something.
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ChrisWiggles
Opinionated SOB
Joined: 12 Mar 2006
Posts: 2529
Location: Seattle
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| Link Posted: Tue Aug 30, 2011 9:11 pm Post subject: |
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As far as white, you need to set the white level/contrast control where it needs to be, as high as possible before the clip/colorshift point. On samsungs, this is usually pretty high.
Then you turn down the backlight (usually pretty low) to achieve whatever desired luminance you wish for your viewing environment. ~40ftl is fine, depending on your taste and ambient lighting you may want to go higher or lower. I like lower for dark movie viewing myself, but if you watch a lot of TV you may like it a bit brighter. Your call.
If it's still too bright with the backlight all the way down, only then should you begin to lower the white level. Lowering the white level from its maxed out (but correct) setting is simply throwing away CR. Always maximize CR with black and white points, and use backlighting to adjust the desired luminace of the display to your taste target.
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Deinorius
Joined: 29 Aug 2011
Posts: 13
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| Link Posted: Tue Aug 30, 2011 10:35 pm Post subject: |
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I already used the AVSHD 709 videos to set brightness, contrast, color and tint without any colorimeter.
But lately it's odd, that I have to set contrast to max 100. When I got the TV the right contrast was 95. Now I have to set 100 and it still isn't really right.
I don't really get it, what changed. That happened before the calibration with my i1LT.
For that calibration I already set backlight down to 6 of 20, which results into 138 cd/mē, about 40 ftL. I already wrote that in my first post. I will try with a lower backlight. I hope, it helps.
For color calibration I have to try more. I can't really do it in the direction of kal's guide. It seems, I have to set xy and then try to match the brightness of all colors to get the deltaE as low as possible.
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Ron W
Joined: 07 Aug 2009
Posts: 807
Location: Mississauga
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| Link Posted: Wed Aug 31, 2011 4:07 pm Post subject: |
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| Deinorius wrote: | I already used the AVSHD 709 videos to set brightness, contrast, color and tint without any colorimeter.
But lately it's odd, that I have to set contrast to max 100. When I got the TV the right contrast was 95. Now I have to set 100 and it still isn't really right.
I don't really get it, what changed. That happened before the calibration with my i1LT.
For that calibration I already set backlight down to 6 of 20, which results into 138 cd/mē, about 40 ftL. I already wrote that in my first post. I will try with a lower backlight. I hope, it helps.
For color calibration I have to try more. I can't really do it in the direction of kal's guide. It seems, I have to set xy and then try to match the brightness of all colors to get the deltaE as low as possible. |
Brightness and contrast interact so if you made any changes to the brightness level it would change the contrast too. I find it ironic despite all this "allegedly" more advanced technology, we are still dealing with the same issues of manufacturers in an attempt to stand out in the maze of televisions in the retailers, tinkering around with their monitors at the expense of accuracy and of course, getting the best possible picture. Joe Kane has talked about this for years and obviously the approach has never changed.
Some have said(even in the CE press) that there is no longer a need for outboard video processors and/or professional calibration BUT as Kal stated, we all know different.
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Deinorius
Joined: 29 Aug 2011
Posts: 13
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| Link Posted: Thu Sep 01, 2011 1:23 am Post subject: |
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Yeah, of course you're right. I could change brightness for a better contrast. But that's not the point. At first, after I got my TV, I could set brightness and contrast without any problem, but that changed. I know displays change with time, but within the first days?
I did a new calibration with another but similar TV today. I did it better than with mine. Of course it's easier now, but this TV was easier to calibrate itself.
Contrast and brightness are the same like mine. With correct brightness contrast isn't the best. On the other side, if I want a correct contrast I can forget my true black. Damn.
But the real problem with this TV was blue. I was able to set all other colors quite well, except of red but it's still in an acceptabel range. Blue is different with a deltaE of 27.
Does we have to live with that blue, or what's a possible way to change that? It's odd we've got the same problems with two different TVs, even if they are similar.
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Ron W
Joined: 07 Aug 2009
Posts: 807
Location: Mississauga
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| Link Posted: Thu Sep 01, 2011 3:41 pm Post subject: |
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| Deinorius wrote: | Yeah, of course you're right. I could change brightness for a better contrast. But that's not the point. At first, after I got my TV, I could set brightness and contrast without any problem, but that changed. I know displays change with time, but within the first days?
I did a new calibration with another but similar TV today. I did it better than with mine. Of course it's easier now, but this TV was easier to calibrate itself.
Contrast and brightness are the same like mine. With correct brightness contrast isn't the best. On the other side, if I want a correct contrast I can forget my true black. Damn.
But the real problem with this TV was blue. I was able to set all other colors quite well, except of red but it's still in an acceptabel range. Blue is different with a deltaE of 27.
Does we have to live with that blue, or what's a possible way to change that? It's odd we've got the same problems with two different TVs, even if they are similar. |
Yep, you have hit on an issue along the lines I touched on above. In the course of looking different, one of the things some of the manufacturers do is play around with the color decoders thus purposefully emphasizing a certain color or colors to differentiate themselves from their competition. The problem is in cases like these there is basically NOTHING you can do about it. Without replacing the entire color decoder, no matter what you do there will always be an emphasis in the blue aspect of the monitors picture. Even with an outboard video processor that can do multiple adjustments at multiple levels and and with color management systems, they can still only do so much. I have a monitor that is a 10 year old RPCRT working beautifully with an outboard processor. The set has an emphasis of about 7% too much in the blue spectrum(not in the grayscale) and even though I can fine tune adjustments, without going outside of the boundaries of the capabilities of the set causing more problems, I just have to live with it and try to compensate in other areas.
Of course, one can find monitors that come out of the store that are more accurate, however, since one can't determine the proper accuracy by eyesight alone, without the proper measuring devices one will never really know until you buy it and get it home.
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Deinorius
Joined: 29 Aug 2011
Posts: 13
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| Link Posted: Mon Sep 12, 2011 4:30 pm Post subject: |
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Just a little, maybe dumb, question. I purchased a retail i1Dis3 Pro and now I read by coincidence that this version will only work with its own iProfiler Software? Am I f*ck*** now, or what is this situation now?
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kal
Forum Administrator
Joined: 06 Mar 2006
Posts: 17860
Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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| Link Posted: Mon Sep 12, 2011 4:36 pm Post subject: |
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| Deinorius wrote: | | Just a little, maybe dumb, question. I purchased a retail i1Dis3 Pro and now I read by coincidence that this version will only work with its own iProfiler Software? Am I f*ck*** now, or what is this situation now? |
The retail Display 3 (officially called the 'i1 Display III PRO') will not work with OEM software due to licensing rules made by X-Rite. So you can't use it with ColorHCFR or ChromaPure (for example). The free ColorHCFR will likely never be able to work with the Display 3 for these reasons no matter which version of the Display 3 (retail or OEM) you purchase.
Kal
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Deinorius
Joined: 29 Aug 2011
Posts: 13
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| Link Posted: Wed Sep 14, 2011 3:25 pm Post subject: |
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Yep, I researched by myself too. What a pity. Well in this case I'm sending the retail version back (after I calibrated all displays connected on my PC... *cough*).
Await my order for the ChromaPure i1 Dis3 Pro Package.  (Help, my purse is killig me...!)
Any more suggestions to this?
Edit: Of course it's clear, ColorHCFR can't support new hardware, if they don't release a new version.
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kal
Forum Administrator
Joined: 06 Mar 2006
Posts: 17860
Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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| Link Posted: Wed Sep 14, 2011 4:56 pm Post subject: |
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| Deinorius wrote: | | Edit: Of course it's clear, ColorHCFR can't support new hardware, if they don't release a new version. |
It's actually more than that: Even if ColorHCFR releases a new version and WANTS to support the Display 3, it's HIGHLY UNLIKELY that they'll be allowed to because of the way that X-rite is doing the licencing of the Display 3.
So long story short: Unless X-Rite changes their licencing policies with the new Display 3, there's no way that ColorHCFR can support the Display 3 even if the ColorHCFR developers say they want to.
Kal
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Deinorius
Joined: 29 Aug 2011
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| Link Posted: Wed Sep 14, 2011 6:04 pm Post subject: |
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I know, I just meant it from the software side without considering this retail/OEM dilemma. 
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Deinorius
Joined: 29 Aug 2011
Posts: 13
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| Link Posted: Thu Oct 20, 2011 8:34 am Post subject: |
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OK, I've got my i1Pro for some time and I calibrated two TVs by now and it works great. I can even get Blue under deltaE 3. Everything else I get below around 0.5. I can upload my summary later, just got another important question.
I noticed that my Samsung UE46D7000 gives different contrast with PS3 and with its intern media player. With contrast 100 on PS3 white point is about 250, with that intern media player I get with the same settings white around 235. What's the reason for that? I don't get it.
And there's another point. I thought I have to set white point around 235 but especially the two guys on the video of the AVSHD 709 disc they suggest to set contrast lower. I don't know the exact white point by now. What would you suggest?
Especially the different contrast of two sources makes me unsure.
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Ron W
Joined: 07 Aug 2009
Posts: 807
Location: Mississauga
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| Link Posted: Thu Oct 20, 2011 3:32 pm Post subject: |
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| Deinorius wrote: | OK, I've got my i1Pro for some time and I calibrated two TVs by now and it works great. I can even get Blue under deltaE 3. Everything else I get below around 0.5. I can upload my summary later, just got another important question.
I noticed that my Samsung UE46D7000 gives different contrast with PS3 and with its intern media player. With contrast 100 on PS3 white point is about 250, with that intern media player I get with the same settings white around 235. What's the reason for that? I don't get it.
And there's another point. I thought I have to set white point around 235 but especially the two guys on the video of the AVSHD 709 disc they suggest to set contrast lower. I don't know the exact white point by now. What would you suggest?
Especially the different contrast of two sources makes me unsure. |
What you are seeing is that different video sources can give you different readings. Your set-up has to be somewhat of a compromise or done with a specific source item in mind that you would use more than the other. Different Blu-Ray players can give you different readings(white point, grayscale and color space) with the same calibration disc. Like monitors, today there is STILL no consistency in performance among the manufacturers. I use to have TWO BR players on my rack, an Oppo and a Panasonic. When doing the calibrations with the disc using the Oppo as my source, it was pretty close to matching the readings from my monitor whereas with those same readings the Panasonic had a distinct "red shift" which would obviously affect grayscale and the white point. I later removed the Panasonic and placed it in another room. The only way you can deal with multiple sources and get accurate readings across the board is with an outboard processor that can do multiple calibrations for multiple sources. Of course, that gets in to considerable extra expense, however, Kal can probably give you additional ideas about that.
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Deinorius
Joined: 29 Aug 2011
Posts: 13
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| Link Posted: Thu Oct 20, 2011 5:43 pm Post subject: |
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OK, nearly as I thought. Sad to read this but it is like it is.
In this case just a last question. What would you suggest where to set white level. Now it would be with the PS3 around 245-250. Is this ok or would you recommend a different setting?
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