Calibrating an LCD LED backlit TV

NEOSJW

Novice Member
Hi Guys,

Just looking for some advice from someone more vastly experienced than myself. When calibrating a TV with a full array backlit LED lighting system with a hardware meter (using Chromapure If that makes a difference) would you use Window, Fields or APL patterns.

Also in your experience would you calibrate with Local Dimming enabled or disabled (even though you plan to use this after calibration). I have read that this should be disabled.

I have read varying opinions on the level of the backlight setting as well, any experience on this also.

Many thanks in advance
Simon
 

DannyTucker001

Active Member
NEOSJW said:
Hi Guys,
Also in your experience would you calibrate with Local Dimming enabled or disabled (even though you plan to use this after calibration). I have read that this should be disabled.


I recently had my Full LED Backlight TV professionally calibrated and it was done with Local Dimming OFF and switched on after the calibration.
 

NEOSJW

Novice Member
DannyTucker001 said:
I recently had my Full LED Backlight TV professionally calibrated and it was done with Local Dimming OFF and switched on after the calibration.

Thanks for that and the more research I do it seems this is probably the preference, rechecking afterwards with Local Dimming enabled to ensure that it hasn't made adjustments to the PQ quality.

Just need to get some confirmation on my other points and I'll be ready to go when my kit turns up from RickyJ.

Thanks
Simon
 

hodg100

Distinguished Member
Simon,

The backlight is set to give the most suitable peak light output for you and your room so there's nothing set in stone. You need to watch what effect it has on contrast though, so always recheck once you've got it set.

I'd use full rasters (window patterns).

As above, calibrate with local dimming off as they mess up the measurements, then set it to taste - I can say that as it's your TV:)

Best

Mark
 

NEOSJW

Novice Member
Mark Hodgkinson said:
Simon

The backlight is set to give the most suitable peak light output for you and your room so there's nothing set in stone. You need to watch what effect it has on contrast though, so always recheck once you've got it set.

I'd use full rasters (window patterns).

As above, calibrate with local dimming off as they mess up the measurements, then set it to taste - I can say that as it's your TV:)

Best

Mark

Thanks Mark,

I appreciate the advice, my hardware turned up today, so hoping to get some quiet time in front of my TV later :)

Thanks again

Simon
 

NEOSJW

Novice Member
Hi Mark,

After spending a bit of time configuring my TV (well hours and hours :D ), i wonder if you have any thoughts on the following.

I have a pretty good set of readings on greyscale, gamma, colour gamut and colour luminance when configuring with Local Dimming on Off and on Low. As soon as it is turned onto Medium / High (which provides the best black level) it takes my gamma reading up to 2.7 average (peaks at 10 IRE and 80 and 90 IRE at 2.94) It also then changes my Blue colour lightness down from 0.4% from target to -16.9%. The others (Hue and Saturation change a little but only by .2 to .3 so not worried about those)

Is this a typical occurrence when using stronger LD levels?

I was also wondering how people have got on configuring 3D, i had a go at it and although not as good as my 2D settings they seem alot better then the original presets. In the 40 to 80 IRE region the greyscale is mostly under 1.5 dE. But the higher and lower IRE's i just can't go any higher or lower on the RGB to get it down further. My 100 IRE is at 14.7 and then 90 is at 8.5 , 20 IRE 2.4 and 30 at 9 dE.

Does this sound about right, my colour gamut and CIE chart are ok, not perfect (some colours are a little out)but certainly better.

Any advice would be great.

Many Thanks

Simon
 

hodg100

Distinguished Member
Hi Simon

The problem is once you engage LD, you mess with the patterns and you can no longer really trust the measurements as a result.

You'll need to use your judgement on black levels v detail crush/colour reproduction. How different do colours actually look when changing between the settings?

It would probably help to know which TV you are working with...Seem to recall seeing you on some LG threads? In which case LD on low would be my favoured choice.

Re 3D, what meter are you using? It needs to be a very good one to get accurate readings low and high scale with the glasses covering the sensor...

HTH:)

Best

Mark
 

NEOSJW

Novice Member
Mark Hodgkinson said:
Hi Simon

The problem is once you engage LD, you mess with the patterns and you can no longer really trust the measurements as a result.

You'll need to use your judgement on black levels v detail crush/colour reproduction. How different do colours actually look when changing between the settings?

It would probably help to know which TV you are working with...Seem to recall seeing you on some LG threads? In which case LD on low would be my favoured choice.

Re 3D, what meter are you using? It needs to be a very good one to get accurate readings low and high scale with the glasses covering the sensor...

HTH:)

Best

Mark

Thanks Mark,

I really appreciate the reply. I am calibrating the LG LW980T (so full array backlit LED lighting). To be fair the colours still look fairly accurate (I switched between expert 1 and 2 with LD Off and on Medium to compare). There is a smudge of detail being lost in the shadows but the black level becomes excellent. I am a bit of a perfectionist so just wanted it to be perfect but I think the actual dE on the luminance of Blue was 6, so maybe not too bad. If I could push the black level down on low then I would be completely happy but sometimes I know you have to compromise :)

I am using a new i1 Display pro (Display 3) from RickyJ at Kalibrate (from the forums) I went for Pro option which includes corrections against a reference device on a number of sources (including a profile in Chromapure for LG LED displays) Therefore assuming it is pretty accurate but I don't know if it has the accuracy to calibrate 3D. To be fair though looking at my first pass of 3D although it's not perfect it is so much more accurate that any of the presets. Infact I would go as far as saying that the depth seems to be better and although a novelty the pop out effects in some films seems to work better after calibration (could just be a placebo effect :) )

Overall very impressed with the new images, I didn't realise how much blue push on the greyscale there is. If you want to have a look at my results please take a look at the LW980 thread on the LG forum section of the site, for my first real attempt I don't think I did that badly :)

Many thanks

Simon
 

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