CCFL LCD "warmup" time

did you also lose some light output as well?

how much of it peak light output in % does the set achieve after the first 15 mins of warm-up time?

how many hours are on your set? there is counter built-in to the user menu on these sets.


considering that you don't notice this by eye, is it possible this could be a meter issue? can you test the meter on another display to see if this behavior persists?


http://www.spectracal.com/downloads/...s%20Enough.pdf

take a look at the table in this article that shows how the typical CCFL-LCD should behave in terms of warm-time

Time Interval: Percent Change

0 to 10 minutes: 234.70%
10 to 20 minutes: 6.19%
20 to 30 minutes: 4.22%
30 to 40 minutes: 3.03%
40 to 50 minutes: 1.10%
50 to 60 minutes: 0.70%
60 to 70 minutes: 0.29%

Perhaps LG cheaped out on some of the internal parts that are related to the backlight. I know LK450/520 owners have experienced issues with the backlight inverter buzzing, which is covered in more detail here. My set has 1000 hours on it and so far the buzzing is the only issue I have.

If you cannot notice this difference when watching normal program material, then you may want to consider this just a minor annoyance when setting up for calibration. I like to leave my TV running for many hours before calibrating it (I just watch a movie or some TV programming while it warms up) and then I leave the meter in contact mode for at least an hour before starting any calibration.

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Wow Dave. . . . yet another thing a meter will do to cause some hang wringing.

I haven't had my D2 for some time now, but I do have my trusty old photo meter that I recorded light output levels with while comparing peak light and the D2. I'll have to dig it out and see where it's at. However last time I did that about 6 months ago (?), it was only about 5 or 6 % down as I remember with about 2600 hours on my 42LD550. I do know when my LG was new it was at about 92 % of peak at 30 minutes or so compared to having it on for several hours. Interesting though.

As a reference, my 5 year old Mitsubishi has I don't know how many hours but estimate 2 1/2 times the hours of the LG, but I never took bench mark readings when it was new. . . just some about 2 years ago and haven't checked it in some time. The trouble is I cranked back light and contrast down on it when I had my D2, but it still looks almost too bright at times when watching at night even with my bias light. The Mits has a common back light setting for all inputs.

Other than that. . . . how is the picture quality? With all the fussing and calibration redos you've done I guess I haven't heard if any of them markedly improved the picture visually. I know I'll get clobbered with "that's a subjective evaluation" but that's what's curious about having meters. Once a guy has a meter all you usually hear about is the numbers, how this metric did this, and that slight change in gamma did that. . . no talk of how it really improved (if any) on what it L@@Ks like compared to a previous set of calibration values.


EDIT: I checked my recorded data from when my LG was new and I had 141 nits peak at a back light of 43 when new after 3 hours of on time. My Mits measured at about 160 at the numerical 11 position about 2 years ago with 2 hours of on time. Will check it again in the next few days if I can.

Well, it does take two to tango. . . and "pointless" is subjective. I just was anticipating what usually happens. A guy learns to flinch ya know. But no, actually what I was asking was a valid question and surely don't want to get your thread closed.

I just noticed that after awhile, folks seem to loose sight of what the calibration is supposed to be for and unless a previous calibration is kept on say, HDMI 4 Expert 2 for a bench mark, how can a person tell how the visual picture quality changed if any? I did this and still have two initial (stabilized) runs on my HDMI4 from over a year ago I keep as a reference. Now, the TV may have drifted, back light change, etc. .. . but that would be common to all the inputs for the most part so still at least some kind of reference. I know my last run through settings was over 8 months ago and still satisfied with them, and when compared to my HDMI 4 benchmark (using the same Blu-ray player) the last settings in HDMI Expert 1, while markedly different number wise, are better visually in nuances of color saturation and dark level detail. But not a "night and day" difference to the eye. All these settings were made using AVS HD709 ( and now sold D2) and then followed by my reference Sea Biscuit movie with key detail scenes. I feel having 1 or 2 personal reference movies are key in determining whether changes in settings actually made any visual improvements, otherwise it's all just numbers. And numbers can mean different things as aspects of equipment limitations and foibles become evident.

I can say that my *current* calibration setup looks better than the previous 2 or 3 runs. If I hadn't been able to detect a few problems visually, then I wouldn't have bothered to pull the meter out of storage.

Bait bitten, Line broken. Better luck next time.

Probably doesn't help you much, but my LK450 does seem to take awhile to "ramp-up" when you increase the backlight setting. When I was trying to fix my peak-white L (which dropped by ~25% by the time 2400Hrs were on the clock) I actualy had to back off of my original "fix." Example:

@150Hrs - set backlight to 30 - got ~101Nits
@2400Hrs - white output was ~75-78Nits.

Pushed backlight up to 38 to get back to 100Nits, watched white output continue to climb to 115, 121Nits over several minutes worth of "free readings." I finally backed down to 33 on the backlight, and now the white output seems stable at ~98-102Nits (after a few hours worth of viewing.) It's usually post-primetime before I dig into any meter-based calibration work.

PS: Looking over your previous posts, I think it might be ok to be concerned about your backlight power supply/drive ...

Not sure what you mean by that. . . except it kind of is more of the same expected here at times and would only continue to propagate it.

As to your situation, I would expect a change since you corrected an obvious issue you saw before redoing it. I had a similar experience to yours when I accidentally transferred settings from one HDMI Expert setting to another and found out a week or so later that my HD DVD player did not look right. "In my case, transferring settings from one input to another is not reliable or accurate. What I mean is the practice of doing one calibration run after another over period of weeks or months because of questioning what gamma to use, or some values don't "look" right , or now a meter is suspected to have marginal accuracy, etc, and previously the first runs were found to be acceptable to an owner. Or, sometimes redoing just to "see" if there is any difference but what is the difference, and no report of any visual differences are ever stated in subsequent posts.

... or it could be that it may take several runs to learn all the quirks of a particular model, and what approaches work best.

For instance on our LG LK series, it's a waste of time to try to use the CMS to correct *saturations* which is something one may not know (or believe) until several attempts have been made.

There's no harm in experimenting ...

Any reason you choose 100 nits for peak white? Just curious. I use back light of 43 , but then use Energy saving which knocks it down about 15 to 20 % for night viewing. Energy Saving at anything but "Auto" will not cause the back light to fluctuate.

Yes, I agree and "have been there" for the same reasons. I'm speaking of the more mature "phase" after all these things have past.

But even then, the question still remains. . . what visual differences did those further runs make? That's what seems to rarely be stated, just that the numbers are now "better". So. .. better how visually?

I say this, because after the learning and curiosity curve you just stated I did the very same thing when I had my D2. . . and after awhile noted no real visual difference with further runs even though numbers may have changed.

But never mind, maybe you aren't really serious in answering anyway. If it's just that an owner likes to try another approach as you say I can understand that to as I have done that, but after awhile I began to wonder why?

And I guess many times it just has become a hobby. . but it would be nice to know even what a hobby accomplishes in visual results on the TV screen

I have noticed similar behavior on my 42LK450, which can making setting backlight during a calibration annoying. I have mine at 40 right now and with a contrast setting of 99, I get light output of 40 fL, which is 137 Nits. I have 1000 hours on my set.

I agree, that's how you learn more about calibration in general and specific to your set. Once CalMANv5 comes out with the added gamut features (like saturation and luminance sweeps), I'll be able to test out all elements and angles of gamut performance and what effect the CMS & Color/Tint controls have on various saturation and stimulus patterns. I do already have a pretty good idea of how it all works together, though.

Ok ... specifics between Current and Current -1 (and -2) runs:

1) {Current -1} had a "feeling" of being a bit too bluish. It turns out I got a wee bit impatient @ 20% and 10% and allowed the greyscale to drift +blue relative to the rest of the greyscale ... also I removed a bit too much green at 90% and 100% ... both mistakes were human error, yet both measured "ok" or "close enough" at the individual measurement point(s)

2) {Current -2} aka "Much CMS experimentation": Introduced various errors in "Brightness" trying to get saturations in line. Again the net result was a mild blue/purple/magenta push.

So yes, one should always check your calibration results by viewing familiar material. This helps determine if something went awry ... OTOH, it probably won't tell you specifically what is wrong, nor will it help you set the grayscale or CMS systems.

I have the same set as Djams and haven't noticed any appreciable increase in warm-up time but then again, that is purely subjective because I have no way of measuring the light output

I believe Michael Chen has stated that our eyes cannot perceive a difference in light output below a 30% change.

http://www.tlvexp.ca/2012/01/setting...u-might-think/

Well that's not very encouraging

I meant that you are probably correct to be concerned about the extended amount of time your set is taking to get from 86% to 100% output. The backlight power supply's health would be the most obvious place to start trouble shooting. This would require having a technician do some testing ...

That being said, I don't really know if this is an actual problem or a natural trait of the set ... being that I've never put a meter on mine until it's been running for 2-3 hours ...

same here, I like to have everything warmed up completely before beginning any calibration runs

and then there is the issue of meter warm-up as well... my C6 reports lower Y values until it reaches the temperature of my display/room temperature

given that I store my meter in a cool place, the longer it has been in storage, the longer it takes to fully warm-up on the display

I do have a light meter but haven't taken the time yet to do a ramp up check. Weather has been too nice, trip up to the cabin, lawn to mow, help the kids with a non starting roto tiller. Heck, it's spring time!

Anyway, I've at least taken note to see if it takes longer to ramp up to "normal" brightness on both my main LCD TVs and I know the Mits does take longer than when new. What I mean by that is it seems visually dimmer than full brightness for at least 40 minutes or so. The LG appears to reach a brighter state in shorter time. The Mits runs at a higher peak brightness of about 160 nits vs LG 141 nits though so that could account for some of it, and that's at a back light level now of only "9" on a 0 to 63 scale.

That said, I still am getting plenty of light output and excellent PQ out of both TVs. We just picked up Thor and Captain America on Blu-ray and watched Thor last night. Amazing sets for both CG and constructed, saturated but not over done colors, and not a bad story line if you are a Stan Lee fan.

We'll watch Captain A this afternoon since the weather is a bit rainy today and think it will also be amazing PQ.

So I wouldn't be concerned about a little longer warm up time as long as it's nothing you notice or you can hear the inverter circuits straining to light up the EEFL tubes in your TV.

Here is a pdf that explains some LCD back light technology and differences, and some very nice graphics and pictures to see these differences. While not specifically for TVs the technology/benefits are the same.

http://www.delphidisplay.com/white_p...s%20-%20v1.pdf

You do have my address

Ok, we are remodeling our lower level (still) and my photo equipment stash is who knows where behind a pile of boxes. But I had some time last night and this AM and used my lux meter. I could also measure in foot candles but used the lux scale just because it gives higher numerical readings and therefore higher resolution. If you want to convert to nits or fl, there are charts for that.

Anyways, my lux meter seems to give lower readings than my photographic light meter. At least this will give you and idea of the rise in light output over time. This is just pretty quick and dirty as they say, but still should give a pretty fair representation of what you were looking for.

Max output after 105 minutes to 3 hours stabilized is 270 lux +/- 2 lux.

Output after specified time:

100 lux @ 3 min. 37%
193 lux @ 15 min 71%
235 lux @ 30 min 87%
251 lux @ 45 min 92%
261 lux @ 60 min 96%
267 lux @ 90 min 98.8%
270 lux @ 105 min 100%

The Back Light output was stable at 270 +/- 2 lux after 105 minutes and monitored for 4 hours total. So in my opinion, from now on, I wouldn't do any setting adjusts on my TV until it was on at least 60 minutes or better still 105 minutes. And, as you can see, it takes an additional 60 minutes to gain the last 8% in light output to max output. I will say that after 45 minutes to 1 hour I really can not tell visually, any "brighter" or better picture with either excellent OTA content or Blu-ray reference movie content.


Well, it's "summer" here already, mom's day and such and plenty of outdoor things to enjoy. Too nice to do much more indoor stuff like this unless it rains and then it's back at the lower level remod.

BTW. . . what are your figures for similar times? I know you said 2 hours to peak output I think.

P.S. A contact type photo sensor was used with the 1330B meter in the style of the D2 puck design. Reading with the TV off and low indirect ambient room light is 0.

Guess no one really cares?

Dead end thread??

Last time I "fall" for this. . . lol.

I wouldn't say that. What you've measured seems to be similar to how my 42LK450's backlight warms up. (I use a C6 colorimeter, however, which might be a bit different from a light meter.)

As such, I like to warm up the set for a couple of hours at least before starting calibration runs. The meter should also be warmed up on the set to get best results in contact mode.