Massive Color Drift Correction for i1 Display Colorimeter - Page 3 - AVS Forum
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post #61 of 95 Old 04-20-2012, 11:49 AM - Thread Starter
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Originally Posted by airscapes View Post

Luminance and RGB are 2 different things. The meter can read the proper brightness (amount of light or luminance) correctly but not the proper color.

Gamma is the difference in luminance form 0 -100% and has nothing to do with color, so it can be accurate and the color reading be very wrong. You can not fix this without using a known good reference spectror meter, and if you had such a meter, you would probably just toss the D2 in the trash and use the spectro since the speed difference would be of no great issue.

Then you display a Red, Green, Blue and white pattern and take readings of each.

The software makes a table of the difference between what the reference meter sees vs what the target meter sees.

Well, the gamma data is based on relative brightness levels so if the absolute level is off that would not affect the delta % values. Therefore, if everything is still linear, then the gamma before and after should look the same.

However, I'm having trouble with the luminance vs RGB levels. The luminance plot I have (see above) has all 3 colors displayed - not the luminance only plot. Therefore, if RED is low shouldn't it show up as low on the RED color luminance chart?

BTW does the i1 Display 2/LT have 3 or four sensors in it? I see the 3 RGB filters, but what is in the 4th hole? Is that a luminance sensor?


The profile procedure then only uses a single white point and the 3 primary colors RGB at a single stimulus (like 75%) to calculate a matrix to stretch or push the meter's (to be profiled) color space to match the reference meter. If things are linear this would appear to correct things. However, if things are not linear is this sufficient. Does the software require a full meter comparison after these 4 measurments to ensure accuracy across the board from low to high saturations and luminance values? The 2 meters should match for all readings not just the initial white and primary values.
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post #62 of 95 Old 04-20-2012, 12:05 PM - Thread Starter
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Originally Posted by PlasmaPZ80U View Post

I'll say it again, proper storage of these meters is essential to maximizing their lifespan (especially for those meters with completely exposed filter arrays). I'm not sure the OP's storage method was 100% optimal.

I believe you had/have an i1 Display 2 meter. I think you even stored it in a hermetically sealed (with desiccant) container. How much useable meter life did you get and what was the error that you experienced?

My feeling is that if temperature and humidity kill these meters the only safe place is the refrigerator in a sealed container. Would have been nice if the manufacturer said that! Cool and dry place is what just about everything made says on the label.
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post #63 of 95 Old 04-20-2012, 12:18 PM
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Quote:
Originally Posted by Plasma54321 View Post

Well, the gamma data is based on relative brightness levels so if the absolute level is off that would not affect the delta % values. Therefore, if everything is still linear, then the gamma before and after should look the same.

However, I'm having trouble with the luminance vs RGB levels. The luminance plot I have (see above) has all 3 colors displayed - not the luminance only plot. Therefore, if RED is low shouldn't it show up as low on the RED color luminance chart?

BTW does the i1 Display 2/LT have 3 or four sensors in it? I see the 3 RGB filters, but what is in the 4th hole? Is that a luminance sensor?


The profile procedure then only uses a single white point and the 3 primary colors RGB at a single stimulus (like 75%) to calculate a matrix to stretch or push the meter's (to be profiled) color space to match the reference meter. If things are linear this would appear to correct things. However, if things are not linear is this sufficient. Does the software require a full meter comparison after these 4 measurments to ensure accuracy across the board from low to high saturations and luminance values? The 2 meters should match for all readings not just the initial white and primary values.

That is the process to profile a meter with Calman. What the software does I do not know, all I can say is it works. My C6 reads very close to the same as the i1Pro once it is profiled. The difference is in the bottom end 10 and 20% stimulus, the i1pro does not work well at that low light level and the C6 readings are more accurate.

You really should read this article about Tri-Stim meters and how they work and why they don't always work well.
http://www.tlvexp.ca/2012/04/do-cali...-stim-devices/
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post #64 of 95 Old 04-20-2012, 12:32 PM
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Quote:
Originally Posted by Plasma54321 View Post

BTW does the i1 Display 2/LT have 3 or four sensors in it? I see the 3 RGB filters, but what is in the 4th hole? Is that a luminance sensor?


The meters actually measure in XYZ data. The filters are suppose to match the XYZ curves for the 1931 Standard observer color matching function.

A color matching function is the process that converts raw spectral data from watts per sterdian per nm into XYZ in candelas. X roughly equates to red, Y roughly equates got green and Z roughly equates to blue. The X curve has a little hump near around violet, the 4th sensor I believe it to pick up that data that would otherwise just be binned into the Z sensor data.

The Y value is what is used as luminance, obviously an actual green color has some X and Z components as well. As you can see any wavelength in the visible spectrum has some Y component.


LL

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post #65 of 95 Old 04-20-2012, 02:22 PM
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Quote:
Originally Posted by Plasma54321 View Post

I believe you had/have an i1 Display 2 meter. I think you even stored it in a hermetically sealed (with desiccant) container. How much useable meter life did you get and what was the error that you experienced?

My feeling is that if temperature and humidity kill these meters the only safe place is the refrigerator in a sealed container. Would have been nice if the manufacturer said that! Cool and dry place is what just about everything made says on the label.

The first one I had I used briefly and returned it after calibrating my displays (got it from Amazon just to try out for the first time... had never calibrated with a meter before).

I bought another later on to keep and use for periodic calibrations and after 6 months or so I thought it had drifted since it profiled my PC monitors with pinkish grays. I got a free brand new replacement from X-Rite after explaining my issue and to my surprise it also left a pink tint to all grays when profiling my PC monitors. So, the 'defective' one I sent in was actually normal and even brand new ones made the grayscale too pink post-cal. So, at this point I had used three of these (non-enhanced meters) with ColorHCFR and they all made the overall image have a pink tint.

The last one I bought was a X2 with CalMAN, an enhanced D2 that only works with CalMAN. This was more accurate from day one and it stayed consistent for the whole time I owned it (as did the other ones I owned previously). Looking back, though, I didn't own any of these for longer than a year and so that may be why I never experienced any drift.

Conclusion: all the standard D2's/LT's I used made the overall image too red and no drift was experienced within the first 6 months to a year of use with proper storage. I kept them in two sealed ziploc bags with a dessicant inside. The enhanced X2 was more accurate initially and maintained its accuracy for as long as I owned it. I've sold the D2 I got as a replacement from X-Rite and my SpectraCal X2 as well.

Since, I never kept any of these past a year I cannot say much about drift over longer periods but I remember reading posts from other D2 owners who had their D2s last for up to 5 years. I'd say these can last anywhere from 2 to 5 years if stored in ideal conditions based on what I read on this forum. They can also go bad in six months or less if directly exposed to the elements (left out in the open without airtight bags or case and no dessicant... also exposure to light and heat).
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post #66 of 95 Old 04-20-2012, 02:45 PM
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Originally Posted by Phase700B View Post

Just following up on Plasma54321 comment about Harbor Freight tools. Interesting you would seek out and have to comment ONLY on my post.

You are incorrect again - Plasma54321 made no such comments. Only airscapes and PlasmaPZ80U did, and I agree with airscapes' assessment - you get what you pay for. Your analogy was 180° off of his, and I pointed that out. No need to get accusatory or attack me over this, even though personal attacks and irrelevant insinuations have become the modus operandi of a few here who cannot participate on a rational, contributory level.

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Typical though.

Indeed, as we continue to wait for any pertinent points to be raised in response to my previous post.

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post #67 of 95 Old 04-20-2012, 08:27 PM
 
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Quote:
Originally Posted by airscapes View Post

That is the process to profile a meter with Calman. What the software does I do not know, all I can say is it works. My C6 reads very close to the same as the i1Pro once it is profiled. The difference is in the bottom end 10 and 20% stimulus, the i1pro does not work well at that low light level and the C6 readings are more accurate.

You really should read this article about Tri-Stim meters and how they work and why they don't always work well.
http://www.tlvexp.ca/2012/04/do-cali...-stim-devices/

That is a very good article and I also read it. . .. too late after I purchased my i1 D2 that was inaccurate and unacceptable in performance.

Some of us may have been more understanding had the vendors been more forthright in declaring they had sold marginal products and also ones that would not stand up to time and required such special storage and handling.
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post #68 of 95 Old 04-21-2012, 12:15 AM
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... And yet I've had zero issues with mine (so far) ... of course it's only ~8 months old ... no complaints ... no "oddly colored" greys.

I don't know of any colorimeters of this design vintage that were meant to "last" more than a year without being recalibrated.

Plus, I didn't spend $600 to calibrate a $524 display ... or spend 8 months trying to "eyeball" something that might remotely resemble a "flat" greyscale.

Sometimes a product is *exactly* good enough (for the price) for a particular task.
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Originally Posted by HDTVChallenged View Post

... And yet I've had zero issues with mine (so far) ... of course it's only ~8 months old ... no complaints ... no "oddly colored" greys.

I don't know of any colorimeters of this design vintage that were meant to "last" more than a year without being recalibrated.

Plus, I didn't spend $600 to calibrate a $524 display ... or spend 8 months trying to "eyeball" something that might remotely resemble a "flat" greyscale.

.


Hmmm. . . I wouldn't spend 8 months doing that either.

Nevertheless, I wouldn't spend another $300 to calibrate a $500 display and have it "age" while in storage so the next time I wanted to use it, it was no longer viable.

Good thing there are discs such as AVS HD709 and Disney WOW to help owners perform Media Assisted Settings.
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post #70 of 95 Old 04-21-2012, 05:35 AM
 
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Also, why should it be too much to expect even a $200-$300 meter to last and be viable?

In the audio world I have two vintage Technics SL-1700 MK2 Direct Drive turntables. They are loaded with sophisticated electronics and even optics for the tone arm functions in semi automatic operation. And they remain fully functional. These devices are elctromechanical with servo feedback drives to maintain speed accuracy and after 35 years still work just fine.

Then there are the 4 Dual turntable I have starting with a 1229 from 1972. Since then, I've added a 1229Q and two Dual 1219s. All of these are intricate mechanical and electrical devices that to this day work as intended as the day they were made. Many that were neglected are even restored to full operation with a little repair and clean up.

And do we even need to go into vintage phono cartridges, that are as delicate as feathers and still deliver superb audio delight?

All of the fore mentioned items and were, for the most part, only $30 to $175 when new.

Not to mention 25 year old laser disc players that still function just fine. These devices , utilize very intricate and sensitive electronics and still operate just fine. So, it's very difficult to excuse a meter that can't last 1 to 3 years or remain usable without purchasing another spectro to make "patches" and put band aids on profile tables to make it work properly. And then for only that particular TV or monitor they were profiled on. . . . and for how long??
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post #71 of 95 Old 04-21-2012, 08:37 AM
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Quote:
Originally Posted by Phase700B View Post

Hmmm. . . I wouldn't spend 8 months doing that either.

Nevertheless, I wouldn't spend another $300 to calibrate a $500 display and have it "age" while in storage so the next time I wanted to use it, it was no longer viable.

Good thing there are discs such as AVS HD709 and Disney WOW to help owners perform Media Assisted Settings.

This is one of the reasons we came up with the "rent a kit" program you don't have to worry about the meter being off from aging.

Derek

CTO / Founder - SpectraCal Inc.
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post #72 of 95 Old 04-21-2012, 09:13 AM
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Quote:
Originally Posted by Phase700B View Post


Good thing there are discs such as AVS HD709 and Disney WOW to help owners perform Media Assisted Settings.

Who is to say Disney's WOW isn't without issues?
Quote:
Originally Posted by Phase700B View Post

Also, why should it be too much to expect even a $200-$300 meter to last and be viable?

In the audio world I have two vintage Technics SL-1700 MK2 Direct Drive turntables. They are loaded with sophisticated electronics and even optics for the tone arm functions in semi automatic operation. And they remain fully functional. These devices are elctromechanical with servo feedback drives to maintain speed accuracy and after 35 years still work just fine.

Then there are the 4 Dual turntable I have starting with a 1229 from 1972. Since then, I've added a 1229Q and two Dual 1219s. All of these are intricate mechanical and electrical devices that to this day work as intended as the day they were made. Many that were neglected are even restored to full operation with a little repair and clean up.

And do we even need to go into vintage phono cartridges, that are as delicate as feathers and still deliver superb audio delight?

All of the fore mentioned items and were, for the most part, only $30 to $175 when new.

Not to mention 25 year old laser disc players that still function just fine. These devices , utilize very intricate and sensitive electronics and still operate just fine. So, it's very difficult to excuse a meter that can't last 1 to 3 years or remain usable without purchasing another spectro to make "patches" and put band aids on profile tables to make it work properly. And then for only that particular TV or monitor they were profiled on. . . . and for how long??

You are going to beat this dead horse until it is pulp. Why do you keep comparing everything that you have that has lasted a long time to your colorimeter? The color filters have a known failure rate. This has been common knowledge for quite some time. Hopefully the sealed filters on the new i1 will last a lot longer. You are correct though that no one knows how long they are going to last, but hopefully it will be a couple of years.

As Derek said, if you don't want to deal with the uncertainty then rent a kit. You can even profile your colorimeter against an i1 Pro

My new favorite game is Save The Titanic

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post #73 of 95 Old 04-21-2012, 09:20 AM
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Originally Posted by Ericglo View Post


You are going to beat this dead horse until it is pulp.

He is in the anger phase.. has not accepted the loss yet.. but it in reality, what is done is done and no amount of crying will fix the problem.. time to get back on the horse and move on!
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post #74 of 95 Old 04-21-2012, 09:22 AM
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Quote:
Originally Posted by Ericglo View Post

Who is to say Disney's WOW isn't without issues?

You are going to beat this dead horse until it is pulp. Why do you keep comparing everything that you have that has lasted a long time to your colorimeter? The color filters have a known failure rate. This has been common knowledge for quite some time. Hopefully the sealed filters on the new i1 will last a lot longer. You are correct though that no one knows how long they are going to last, but hopefully it will be a couple of years.

As Derek said, if you don't want to deal with the uncertainty then rent a kit. You can even profile your colorimeter against an i1 Pro

+1 - thanks for bringing some rationality back to this discussion.

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post #75 of 95 Old 04-21-2012, 09:50 AM
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Originally Posted by airscapes View Post

He is in the anger phase.. has not accepted the loss yet.. but it in reality, what is done is done and no amount of crying will fix the problem.. time to get back on the horse and move on!

I agree, you don't see me still complaining about my professional calibration that wasn't all it was supposed to be. It's prudent advice to consider such things as a learning experience and move on. Sometimes that's the best you can do.
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post #76 of 95 Old 04-21-2012, 12:03 PM - Thread Starter
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Quote:
Originally Posted by sotti View Post

The meters actually measure in XYZ data. The filters are suppose to match the XYZ curves for the 1931 Standard observer color matching function.

The Y value is what is used as luminance, obviously an actual green color has some X and Z components as well. As you can see any wavelength in the visible spectrum has some Y component.

So if I understand what you are saying, the grayscale measurement only consists of the GREEN or Y component (of the XYZ system), therefore my OLD and NEW plots for luminace and gamma are similar.

Then, why when adjusting the white point, one balances all 3 colors to 100% as the goal, the colorimeter must read the RED and BLUE colors to allow this adjustment? I'm not getting it. Why some of my charts are similar and some are not? It seems like they should all be out of whack.
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post #77 of 95 Old 04-21-2012, 01:17 PM
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Quote:
Originally Posted by Plasma54321 View Post

So if I understand what you are saying, the grayscale measurement only consists of the GREEN or Y component (of the XYZ system), therefore my OLD and NEW plots for luminace and gamma are similar.

Then, why when adjusting the white point, one balances all 3 colors to 100% as the goal, the colorimeter must read the RED and BLUE colors to allow this adjustment? I'm not getting it. Why some of my charts are similar and some are not? It seems like they should all be out of whack.

The Y value is luminance, so if the Y filter didn't change much, then luminance response would measure similarly given the that the display is still similiar to when you measured it originally.

Color is the ratio of X to Y to Z. So if the X filter is off, then it will change the ratio so you'll get an entirely different color reported back than you are measuring.

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post #78 of 95 Old 04-21-2012, 03:55 PM
 
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Originally Posted by airscapes View Post

He is in the anger phase.. has not accepted the loss yet.. but it in reality, what is done is done and no amount of crying will fix the problem.. time to get back on the horse and move on!

^ ^ ^ This is "On Topic"?

Not really. . . it's just that others, even you, make comparisons and analogies, but apparently only "certain" individuals are valid.

Some just like to argue, bash and demean to no end and stir the pot.

Besides.. as someone else said. "It a free forum with open viewpoints".


__________


V____V____V This is "on topic"?
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post #79 of 95 Old 04-21-2012, 03:58 PM
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Originally Posted by Phase700B View Post

Not really. . . it's just that others, even you, make comparisons and analogies, but apparently only "certain" individuals are valid.

Some just like to argue to no end and stir the pot.

let's stay on topic here and keep it objective

sarcasm and cynicism do not move forward the technical discussion
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post #80 of 95 Old 04-24-2012, 05:01 PM
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I think my I1D2 has drifted too, only had it for a week. Couldn't find driver on Xrite site, it's discontinue. When I do my CMS calibration, it's shows my red and blue are under saturated. Crank up blue and red to 100 and still not working.
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post #81 of 95 Old 04-24-2012, 05:05 PM
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Quote:
Originally Posted by kanti123 View Post

I think my I1D2 has drifted too, only had it for a week. Couldn't find driver on Xrite site, it's discontinue. When I do my CMS calibration, it's shows my red and blue are under saturated. Crank up blue and red to 100 and still not working.

I suspect your issue is not drift but rather initial accuracy. You may be able to live with the grayscale errors this meter leaves behind, but the gamut errors are harder to ignore.

Also, if your primaries start out undersaturated in custom color space at defaults, then nothing with move them outward (increase saturation). If the latter is the case, then you don't have a meter issue.
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post #82 of 95 Old 10-09-2012, 10:59 PM
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I just re-measured my Panasonic plasma and compared the measurements to ones I took in May 2012 (5 months ago). My Display Lt is reading blue higher than it did in May, so my red hasn't drifted but in fact my blue has. My blue readings back in May were all in line with red and green across the grayscale and now the blue readings are about 110% across the grayscale, i.e. my color temp has gone from 6500K to about 7250K.

Could my TV set have drifted or is it more likely that my Display Lt has drifted? If the latter, then can I use my TV set as a reference and create a manual correction matrix for use in HCFR?
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post #83 of 95 Old 10-09-2012, 11:14 PM
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Could my TV set have drifted or is it more likely that my Display Lt has drifted? If the latter, then can I use my TV set as a reference and create a manual correction matrix for use in HCFR?

No you can't use your TV set.

Your TV set is not that stable, and the error would compound.

If you don't trust your meter, then it's time to get a new meter (buy or rent).

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post #84 of 95 Old 10-10-2012, 05:26 AM
 
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Originally Posted by daMaster View Post

I just re-measured my Panasonic plasma and compared the measurements to ones I took in May 2012 (5 months ago). My Display Lt is reading blue higher than it did in May, so my red hasn't drifted but in fact my blue has. My blue readings back in May were all in line with red and green across the grayscale and now the blue readings are about 110% across the grayscale, i.e. my color temp has gone from 6500K to about 7250K.
Could my TV set have drifted or is it more likely that my Display Lt has drifted? If the latter, then can I use my TV set as a reference and create a manual correction matrix for use in HCFR?

The TV may have drifted, but more likely the i1 meter did. They are known for drift with age due to deterioration of the color filters. You can buy an i1 Pro spectrometer to "profile" or correct the errors in your i1 Display colorimeter, but you will have to do that periodically since the meter will continue to drift.

In other works, you have to buy or rent a meter to make sure your i1 Display is close to accurate. Or buy another meter which still may drift. These are well known issues with hobbyist grade meters unfortunately.

Recalibration is one thing, deterioration is another.
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post #85 of 95 Old 10-10-2012, 07:36 AM
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Originally Posted by Phase700B View Post

In other works, you have to buy or rent a meter to make sure your i1 Display is close to accurate. Or buy another meter which still may drift. These are well known issues with hobbyist grade meters unfortunately.

With all meters.

Pros have the same issues, they just understand that recalibration is part of owning any precision instrument.

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post #86 of 95 Old 10-11-2012, 09:54 AM
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Originally Posted by sotti View Post

With all meters.
Pros have the same issues, they just understand that recalibration is part of owning any precision instrument.

That makes sense but it does open up another question, and that is how often should the instruments be re-calibrated? I know there isn't any black and white answer for that because all meters are different from consumer grade (hobbyist) to professional. It seems to me that unless the user has a perceived change in the performance of their tv (real or imaginary), then re-checking the calibration shouldn't be done unless they have recently re-calibrated their meter, period. Otherwise, issues like this come up and you don't know if the problem lies with the tv or the meter(s), and you can spend a lot of time chasing your tail. For a lot of us (some of us more OCD than others smile.gif), checking and tweaking is a hard habit to break and that can be very disconcerting if the meters aren't kept in perfect (or as close as is possible) condition, which can be costly. Sort of like the dark side of calibrations. I almost wish I hadn't started the slippery slope of calibrating (I know, I can hear the groans and the hands slapping foreheads now) but then I look at my pq.....................
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post #87 of 95 Old 10-11-2012, 12:23 PM
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Originally Posted by Otto Pylot View Post

That makes sense but it does open up another question, and that is how often should the instruments be re-calibrated? I know there isn't any black and white answer for that because all meters are different from consumer grade (hobbyist) to professional. It seems to me that unless the user has a perceived change in the performance of their tv (real or imaginary), then re-checking the calibration shouldn't be done unless they have recently re-calibrated their meter, period. Otherwise, issues like this come up and you don't know if the problem lies with the tv or the meter(s), and you can spend a lot of time chasing your tail. For a lot of us (some of us more OCD than others smile.gif), checking and tweaking is a hard habit to break and that can be very disconcerting if the meters aren't kept in perfect (or as close as is possible) condition, which can be costly. Sort of like the dark side of calibrations. I almost wish I hadn't started the slippery slope of calibrating (I know, I can hear the groans and the hands slapping foreheads now) but then I look at my pq.....................

NIST certification is only good for 1yr, so you can see where NIST must think the meters don't drift enough until after a year to invalidate their calibration results.

Granted all meters are designed differently so they will all age differently, but nobody is getting meters re-calibrated on anything shorter than 1yr increments. That said the amount of drift you see in a high end meter like a K-10, Jet 1211 or even a i1 Pro is pretty small at 1yr and with the i1 Pros we see some of them coming in 3 and 4 years out that are still within factory specs.

Joel Barsotti
SpectraCal
CalMAN Lead Developer
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post #88 of 95 Old 10-11-2012, 12:40 PM
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^^^^ that's good to know. smile.gif
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post #89 of 95 Old 10-11-2012, 01:32 PM
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It shows the clear reason why pros have to purchase higher quality to minimise design limitations.

I spoke directly with Jeti about NIST regarding my jeti1211, pretty concluded with the calibration is more of a check and a NIST resert on a yearly basis, the actual change or drift with the device is typically only as much as the design deviation.
You get what you pay for, expect no less.

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post #90 of 95 Old 10-11-2012, 02:09 PM
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Quote:
Originally Posted by sotti View Post

NIST certification is only good for 1yr, so you can see where NIST must think the meters don't drift enough until after a year to invalidate their calibration results.
Granted all meters are designed differently so they will all age differently, but nobody is getting meters re-calibrated on anything shorter than 1yr increments. That said the amount of drift you see in a high end meter like a K-10, Jet 1211 or even a i1 Pro is pretty small at 1yr and with the i1 Pros we see some of them coming in 3 and 4 years out that are still within factory specs.

Can the i1Pro's be re-calibrated (not just re-certified) if you send it to X-Rite directly? Has anyone ever needed to do this, given that you see units 3-4 years past the expiration of NIST certification that are still within spec?

What does SpectraCal do when you send in the i1Pro to them?

Basically, for a DIY user who owns a i1Pro that is outside of NIST certification, do they need to worry about re-calibration? If so, at what point (how many years since the last NIST Cert)?
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