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Author Topic: Is The P221W Still Worthwhile?  (Read 7524 times)
digitaldog
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« Reply #20 on: November 10, 2010, 02:39:55 PM »
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Well Andrew, it's two different computer programs. Each has its own math. All the calibration settings were the same for both.

Exactly. And that’s not any insurance that the results of your preferences are due to the type of profile that was built (LUT vs Matrix). The math is different. Make all the settings identical, you get identical results (color appearance?). I would guess not.

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The most tangible difference was that I could only make a matrix profile with Spectraview, and I had the option to make an LUT profile with BasicColor, which I did.

But that doesn’t explain what you said, at least scientifically. It doesn’t prove that the LUT or Matrix profile had anything to do with the preference you have of a match. And I wouldn’t expect it to anyway.
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« Reply #21 on: November 10, 2010, 02:52:54 PM »
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Exactly. And that’s not any insurance that the results of your preferences are due to the type of profile that was built (LUT vs Matrix). The math is different. Make all the settings identical, you get identical results (color appearance?). I would guess not.

But that doesn’t explain what you said, at least scientifically. It doesn’t prove that the LUT or Matrix profile had anything to do with the preference you have of a match. And I wouldn’t expect it to anyway.

I wasn't scientifically trying to prove anything; only drawing together logical inferences, which as I said are not necessarily determinative. It wouldn't be fair for me to suggest that if you have a better, scientifically-grounded idea of why BasicColor would have given me a preferable result to Spectraview you could tell us, because you'd have to see the differences which you aren't able to do, and you'd need to know the internals of both packages and the theoretical implications of any differences between algorithms for outcomes, a tall order which we won't resolve here and don't need to for the purposes of the OP. He just needs to know there is a procedure and there are options he can play with at little risk to himself and sees what works best for him.
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Mark D Segal (formerly MarkDS)
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« Reply #22 on: November 10, 2010, 03:09:14 PM »
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I wasn't scientifically trying to prove anything; only drawing together logical inferences, which as I said are not necessarily determinative.

I think the consensus (at least among two of us) is the statement “Spectraview II is fine if all you want are matrix profiles and they are fine if the display is perfectly linearized.” doesn’t wash.

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It wouldn't be fair for me to suggest that if you have a better, scientifically-grounded idea of why BasicColor would have given me a preferable result to Spectraview you could tell us, because you'd have to see the differences which you aren't able to do, and you'd need to know the internals of both packages and the theoretical implications of any differences between algorithms for outcomes, a tall order which we won't resolve here and don't need to for the purposes of the OP. He just needs to know there is a procedure and there are options he can play with at little risk to himself and sees what works best for him.

I don’t know why you prefer one over the other since I have no idea if you tried to produce matching results with dissimilar calibration targets. I don’t even know why you prefer one over the other, you simply said:
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I am reporting on real-world results I achieved using both approaches (matrix via Spectraview and LUT via BasicColor Display) on my new PA271W display. I would not have spent the extra 175 USD on BasicColor if I saw that the screen to print match I achieved with it was no better, but it was.

It makes it sound, at least in that snippet that you were unable to produce a screen to print match with SpectraView (but with what settings?).
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Andrew Rodney
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« Reply #23 on: November 10, 2010, 03:09:24 PM »
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Well Andrew, it's two different computer programs. Each has its own math. All the calibration settings were the same for both. The most tangible difference was that I could only make a matrix profile with Spectraview, and I had the option to make an LUT profile with BasicColor, which I did. To tell you what other factors account for the difference in outcomes I cannot because I was not a developer of either package and I'm not a colour scientist; but I do have a keen pair of eyes and a brain so I can see outcomes and then I rely on logical deduction, which I admit may not tell the whole story. For all I know there may be other reasons, but I can only point to the one difference of parameters between them I know for sure because i was the one who did it.

SVII is using internal custom calibration of NEC sensor, basICColor doesn't. That may result in different profiles. Did you also compare basICColor LUT profile with basICColor matrix profile, and basICColor matrix profile with SVII matrix profile?
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Mark D Segal
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« Reply #24 on: November 10, 2010, 03:35:08 PM »
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I think the consensus (at least among two of us) is the statement “Spectraview II is fine if all you want are matrix profiles and they are fine if the display is perfectly linearized.” doesn’t wash.

I don’t know why you prefer one over the other since I have no idea if you tried to produce matching results with dissimilar calibration targets. I don’t even know why you prefer one over the other, you simply said:
It makes it sound, at least in that snippet that you were unable to produce a screen to print match with SpectraView (but with what settings?).

Andrew, IF the display is perfectly linearized, makes no difference whether we use matrix or LUT. IF it isn't, it could, because then you need more data points to more accurately describe the behaviour. So the question is whether the display really is perfectly linearized either out of the box or after calibrating it using DDC to set the basic calibration targets. I have debatable evidence about that relating specifically to my display, but I'm not going to be drawn into that discussion here and now.

I told you why I prefer one over the other: the screen to print match was better. As I told you, I used the same calibration settings for both. You asked for the settings: D65, L*, 110 cd/m2. Hope that helps.

BTW, I don't want to exaggerate the differences in outcomes between these packages. They aren't THAT far apart, but for me, just enough to have preferred using BasicColor. BTW, the same NEC display does use a version of BasicColor for the European issue of the monitor, so there is nothing particularly exotic about this.
 
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Mark D Segal (formerly MarkDS)
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« Reply #25 on: November 10, 2010, 03:38:46 PM »
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SVII is using internal custom calibration of NEC sensor, basICColor doesn't. That may result in different profiles. Did you also compare basICColor LUT profile with basICColor matrix profile, and basICColor matrix profile with SVII matrix profile?

This is interesting. Could you please explain to me how you know that BasicColor doesn't use the custom calibration of the NEC sensor. If true, of course the measurements would not be the same and therefore the outcomes should differ.

I did not make the additional comparisons you mention, because I wasn't in a colour-management derby - I was just trying to get the results I wanted and I stopped when I did.
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Mark D Segal (formerly MarkDS)
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« Reply #26 on: November 10, 2010, 03:53:31 PM »
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This is interesting. Could you please explain to me how you know that BasicColor doesn't use the custom calibration of the NEC sensor.

A representative from NEC that is here on this forum (Will H I think) has pretty much said as much (not directly in reference to BasICColor but he has said that only SVII has access to the calibration tables in the custom puck).

Cheers, Joe
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Mark D Segal
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« Reply #27 on: November 10, 2010, 04:13:23 PM »
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A representative from NEC that is here on this forum (Will H I think) has pretty much said as much (not directly in reference to BasICColor but he has said that only SVII has access to the calibration tables in the custom puck).

Cheers, Joe

Correct - I saw that post from November 2nd in another thread. I'd like someone from BasicColor to confirm whether or not their program properly uses the data from the NEC version of the i1 Display 2, and if it doesn't, what it does instead to produce really good profiles for this display.
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Mark D Segal (formerly MarkDS)
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« Reply #28 on: November 10, 2010, 04:41:29 PM »
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I told you why I prefer one over the other: the screen to print match was better. As I told you, I used the same calibration settings for both.

That’s your first mistake. You have to season to taste the settings to get a match. You may have hit the magical seasoning first with package A, doesn’t mean package B could not hit it (or produce a better match). Again, I’m happy you are happy with the package you used and got a match first time out. It says little if anything useful however about the benefits or lack thereof of one type of profile versus another or for that matter, which package would ultimately produce a better end result.

One thing is clear, given the display you used and the cost of both software options, one cost more than the other.
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Andrew Rodney
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« Reply #29 on: November 10, 2010, 04:59:11 PM »
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That’s your first mistake. You have to season to taste the settings to get a match. You may have hit the magical seasoning first with package A, doesn’t mean package B could not hit it (or produce a better match). Again, I’m happy you are happy with the package you used and got a match first time out. It says little if anything useful however about the benefits or lack thereof of one type of profile versus another or for that matter, which package would ultimately produce a better end result.

One thing is clear, given the display you used and the cost of both software options, one cost more than the other.

You have a point, BUT, the less futzing around I need to do to get the result I want the happier I am. Time is money. I think the path I suggested to Bruce is a logical way to determine step-by-step how much more he needs to spend to get what HE needs. We're not disagreeing that either profiling package can produce good results, and you may well be right that with enough messing around between the two they can probably converge. I think we agree it's best to use the colorimeter designed for the display, and I expect we agree that a Spyder 2 may be inadequate for the display he has in mind. And we agree that CEDP won't cut it for him if he wants to access hardware calibration using DDC. But he has CEDP and a Spyder 2. So he buys the P221W, and experiments with what he has. If he's happy he stops, if he isn't, his next stop is the Spectraview 2 package with the NEC i1 Display 2 colorimeter, because that way he gets the profiling package designed for this display. If he runs into issues with Spectraview II, at no cost he can download BasicColor Display and try the demo for a couple of weeks and see whether he likes it better.

My 2 cents and I now need to move on. As I said, time is money.
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Mark D Segal (formerly MarkDS)
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« Reply #30 on: November 10, 2010, 05:47:46 PM »
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You have a point, BUT, the less futzing around I need to do to get the result I want the happier I am. Time is money.

I’m just trying to figure out where you are coming from based on your posts to Bruce. There’s no question that time is money etc. I suppose you decided at some point after getting SpectraView you had to have another $175 package. But I don’t understand the points you’ve made about LUT vs. Matrix profiles with respect to SpectraView then the points that the additional software package you are recommending to Bruce is producing better results based on your tests.

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I think the path I suggested to Bruce is a logical way to determine step-by-step how much more he needs to spend to get what HE needs.

And I don’t see it at all. First was the point that he or others might need this secondary package because unlike SpectraView, it makes LUT profiles. The testing and science to come to that conclusion don’t wash for the reasons I’ve outlined.

Then you say you got better screen to print matching with this secondary package and I’ll grant you that given some arbitrary calibration targets, you got there with this package but you might easily have seen the opposite with SpectraView based on some differing arbitrary targets (or a different viewing condition). Its unclear if you can or cannot produce a match with SpectraView (I can’t fathom why not).

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And we agree that CEDP won't cut it for him if he wants to access hardware calibration using DDC. But he has CEDP and a Spyder 2.

The question which remains unanswered from you is why anyone with a SpectraView would need CEDP or BasicColor. Its probably not that SpectraView can’t (or will not, or doesn’t need) to create a LUT profile. What’s the justification for spending $175 as you did, to handle a display that was designed from the ground up to use its own host product? If there is some superiority in CEDP/BasicColor, I’m all ears, but none of your testing, at least as described here proves that claim.
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Andrew Rodney
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« Reply #31 on: November 10, 2010, 06:33:02 PM »
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I’m just trying to figure out where you are coming from based on your posts to Bruce. There’s no question that time is money etc. I suppose you decided at some point after getting SpectraView you had to have another $175 package. But I don’t understand the points you’ve made about LUT vs. Matrix profiles with respect to SpectraView then the points that the additional software package you are recommending to Bruce is producing better results based on your tests.

And I don’t see it at all. First was the point that he or others might need this secondary package because unlike SpectraView, it makes LUT profiles. The testing and science to come to that conclusion don’t wash for the reasons I’ve outlined.

Then you say you got better screen to print matching with this secondary package and I’ll grant you that given some arbitrary calibration targets, you got there with this package but you might easily have seen the opposite with SpectraView based on some differing arbitrary targets (or a different viewing condition). Its unclear if you can or cannot produce a match with SpectraView (I can’t fathom why not).

The question which remains unanswered from you is why anyone with a SpectraView would need CEDP. Its probably not that SpectraView can’t (or will not, or doesn’t need) to create a LUT profile. What’s the justification for spending $175 as you did, to handle a display that was designed from the ground up to use its own host product? If there is some superiority in CEDP, I’m all ears, but none of your testing, at least as described here proves that claim.

Andrew, I never said he needs CEDP. I don't recommend it with this display, and I didn't. The point is he has it already, so why not try using it - the marginal cost excluding his time is zero. If he's happy with this, he can avoid spending 250 bucks on the Spectraview package. If he's not happy with it, then he spends. That's all. This is very straightforward thinking about incremental results versus incremental cost and there is nothing to argue about with this.

And as far as matrix vs LUT profiles, I've explained a line of reasoning which turns around how linear the display really is, which from experience I've had I think we can't be sure of - the jury may be out on that one - there's a bunch of evidence and considerations I've been through on this matter with NEC and other specialists in CM - too much to get into here, I don't have time for it. You should know me well enough by now that I don't shoot from the hip - there's background. I already agreed with you that given enough futzing around between the two types of profiles and packages perhaps they could produce very similar results, but I didn't spend my time doing that.  So let's stop arguing about that too.

I recommended the possibility of using BasicColor simply because right out of the box I got a better outcome with it than I did with Spectraview. A version of BasicColor is packaged with the European marketing of this display, so no big deal here. But if he doesn't need it, he doesn't need it. He'll know that if he gets to the stage of using Spectraview II and sees whether or not he can achieve satisfaction with it. The idea of trying a 3rd party package with this display was suggested to me by no other than NEC itself in the context of some issues I was having colour managing it.

I understand fully where you are coming from, the principles involved here have been clarified, the experience reports are done and we all know what I did and didn't do and why, the advice I provided is fiscally prudent, and I have nothing more to contribute to this discussion, so I am ending my participation in this thread.
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Mark D Segal (formerly MarkDS)
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« Reply #32 on: November 10, 2010, 09:17:37 PM »
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Thanks for all the advice.

It's nice to see how politely people here disagree with each other.  Almost Vulcan!

After some dithering (pun intended) I pulled the trigger and ordered the P221W-BK-SV decideding to get the Spectra View bundle.  I was leaning towards going up to the PA series but the doubling in cost to go to the PA241 for a increase from 95.5% to 98.1% of the aRGB space just wasn't justifiable (yes, I know it has more bit-depth in LUT land too).

I found it strange that the PA231 which appears affordable appears to have much less reach into the aRGB space than even the P221 (it lists itself as 72% of NTSC and I believe that the NTSC space is smaller than aRGB).

My Spyder2 will be off to a new home (I have a friend who is staring out as a commercial illustrator and her monitor's calibration makes mine look like a Barco reference monitor).

I'll keep CEDP for now as I should be able to use it on other monitors (wonder how it will work with the NEC re-branded puck)
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« Reply #33 on: November 11, 2010, 01:52:34 PM »
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That’s your first mistake. You have to season to taste the settings to get a match.

"Season the settings to get a match?"  It's been an amusing thread... 

In Europe, SpectraView Profiler includes a display monitor with hood, custom calibration software developed by basICColor, and each display is individually certified. (http://www.necdisplay.com/supportcenter/monitors/spectraview2/faq/) The European market is arguably more demanding than the North American market.

LUT profiles are widely accepted as giving more accurate profiles, both visually and statistically, than matrix profiles, because theoretically, a LUT profile is better able to handle non-linearities in the system - that's why 3-D LUT profiles were developed.

From the same NEC reference above:
QUESTION: Why doesn't SpectraView offer an option to make full 3D LUT type ICC/ColorSync profiles in addition to the current shaper/matrix profiles?
ANSWER: The LCD panels used in the SpectraView displays have excellent color linearity characteristics and can be characterized using the much simpler shaper/matrix profiles. Accurate 3D LUT profiles require a minimum of around one hundred measurements (and up to several hundred) to generate the necessary data and offer very little advantage despite the large increase in measurement time. Additionally there are some compatibility issues with various software applications when using 3D LUT type display profiles.

So NEC says LUT profiles "...offer very little advantage."  Yup.  And sometimes that "very little advantage" is important to the discriminating user. In Europe, it's a no-brainer - use BasICColor to make a 3-D LUT profile.  Compatibility issues with LUT monitor profiles?  Name one!  Not Photoshop, LR, or any of the software that I've used for years.

As for the differences Mark found between using a matrix profile and LUT profile, first off, he's making comparisons using the same hardware - both monitor, computer, and colorimeter, so those variables have been eliminated. The NEC software, as Mark pointed out, is limited by the fact that SpectraView (North America) is unable to make a LUT profile, so it's handicapped to begin with. No option, no choice.  As was pointed out by Czornyj, he could make a matrix profile and LUT profile with BasICColor and compare both to prove the point, but undoubtedly you'd then state that the BasICColor matrix profile is not as good as the NEC matrix profile, or find some other problem with the comparison. The real issue is which software package is capable of giving more accurate results.

SpectraView and BasICColor each have their own calibration routine that uses DDC to access the internal monitor LUTs, but it's not possible to compare the accuracy of each calibration, because there is not access to the calibration data for both.  Presumably, Mark was calibrating to a gamma 2.2 TRC with SpectraView, and to a CIECAM02 TRC with BasICColor.  Again, SpectraView II is just not up to the task of using a more modern, visually accurate TRC (although the European BasICColor software is), as using a CIECAM02 TRC may give a better visual match to his prints. After all, that's why it was developed.

Next, in profiling, a 16-bit LUT using CAT02 chromatic adaptation (from CIECAM02) is more likely to give an accurate profile, as determined visually or statistically, than a simple matrix-based profile using ____ (none?, von Kries?, linear Bradford?) chromatic adaptation. (AFAIK, SpectraView II doesn't even tell you what, if any, chromatic adaptation it uses. Do you know?)  It is widely accepted that matrix based profiles are smaller in filesize, but are somewhat less accurate, whereas LUT based profiles are larger in filesize and generally more accurate (but may sacrifice smoothness). In Mark's case, determining which gives a more accurate profile can be verified visually (which he did!), as well as by comparing the statistics on both profiles using the same hardware. But I can already hear you: "The colorimeter is not a $50,0000 reference spectrophotometer!!!"

Even if the hardware measurement device has some inherent inaccuracy or "offset," it will not affect this statistical comparison. There is no reason to expect that a profile that gives larger errors will somehow be "more accurate" than one that gives small errors, given that the same device is used to make the measurements that were used to build the profile as well as to verify the measurements; a perfect profile would show an error of zero for all data points or colors, and a poor profile will show large errors.  Of course, there may be some systematic error due to the inaccuracy of the colorimeter, causing the colors to be "off" compared to a reference instrument, but there is NO WAY that a profile with a LARGER verification error, built from data from the same measurement device, is going to have greater absolute accuracy than a profile built with data from the same device that has a LOWER verification error.  The profiling app has no way to know whether or not the data it receives from the colorimeter is accurate, or to compensate for an "inaccurate" colorimeter.  The profiling apps's job is to make a profile that can output color with minimal error - as measured by the device that generated the data used to build the profile.  That error can be measured - preferably with deltaE2000 - for comparison purposes.

Verification routines are useful to compare different profiling applications (or settings within one app) to see which gives the lowest error, with the understanding that the absolute accuracy may be off.  Of course, if the accuracy of the device is off a lot, it's visibly apparent.  If two or more measurement devices give comparable results, (say, an Eye-One Pro and a Display2) and images shown using the profiles look appropriate, then the absolute error of the devices is likely to be small.  In addition, if the measurement device is traceable to NIST, as with a certified Eye-One Pro, any inaccuracy of the device is likely inconsequential in real-world use. This is, in fact, the basis for certified monitor calibration by SWOP and GRACoL and the basis for virtual proofing. (http://files.idealliance.org/certifications/cert_docs_2010/idealliance_proofing_cert_19h.pdf)  Of course, DeltaE 2000 should be used for this verification and certification, because the older delta formulas are simply not accurate enough and do not correlate well with visual errors. The reason for this is discussed at the end of the Idealliance reference.

NEC claims that the shaper-matrix profiles from SpectraView (North America) are "good enough."  Mark's experience was that for him, they were not.  Mark has an excellent eye for color, and he's very careful in testing and he is not one to jump to more complicated or expensive solutions without good reason to do so.  The matrix profiles that he made with SpectraView visually failed, and the LUT-based profiles made with BasICColor give better results, visually and statistically.  I think there is a reason that the European market demanded certified panels and BasICColor.  If the NEC matrix profiles are good enough for you (or anyone else), fantastic!  That doesn't mean that they're good enough for everyone.



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« Reply #34 on: November 14, 2010, 12:43:47 PM »
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First Impressions.

I've had the P221W for a couple of days now and have been adjusting it.  I've settled on D50, 2.2, 100cd/m^2 & a contrast ratio of 300:1.  The Average dE is 1.04 and Maximum 1.56 (1.59 if Black Values included).  I selected 52 Calibration & Profile Steps in the preferences and "Extended luminance stabilization time" in the preferences due to the low target illumination.

My test print is the Pixl test image output to a Epson 2880 on Ultra Premium Luster.  The test image's native resolution was 300dpi which resulted in an image size of 11.247 x 7.803.  I'm assuming it was designed for A4 paper so I changed the resolution to 360dpi with "Resample" turned off resulting in an image dimensions of 9.37 x 6.50 which I then printed on 8 1/2 & 11" stock.

I used the Ultra Premium Luster Profiles from Epson with "Super" selected, Rendering Intent set to "Perceptual", Black Point Compensation checked as was simulate Black Ink & Paper Color in the "Proof Setup"

In the CS4 Print Dialog I set "Color Management" to "Document" (Profile: AdobeRGB (1998)), PhotoShop Manages Colors, Printer Profile to Spr2880 UPrmLstr SprPhto.icc, Rendering INtent to "Perceptual" with "Black Point Compensation" checked so my print deiver agrees with the Soft Proof Settings.

I set the Epson print driver to use the correct Media & Print Quality settings (Ultra Premium Luster, Super Quality, High Speed Disabled) and the Mode of (Off: No Color Adjustment)

My light source for print viewing is a Luxo Lamp with a 13W 5000K "Daylight" compact fluorescent.  The ambient light sensor in SpectraView reads the colour temperature of the light source as 4300K but I found using D45 the whites had a noticeable red-brown tint.

Yes, I know, I should have a better light source but I'm still working on what my viewing requirements are.

I'm quite happy with the results.  The display is much closer to the output now.  The blue in the sky of the center image of the target is slightly more saturated and the detail in the right stocking is darker as well but skin tones look bang on.

However, some images I printed earlier the prints look richly saturated but the soft proofs look washed out and muddy.
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« Reply #35 on: November 14, 2010, 03:10:52 PM »
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The European market is arguably more demanding than the North American market.

LUT profiles are widely accepted as giving more accurate profiles, both visually and statistically, than matrix profiles, because theoretically, a LUT profile is better able to handle non-linearities in the system - that's why 3-D LUT profiles were developed.

Hogwash and nonsense. The key word above is arguably unless you can point to something other than a personal opinion here. Otherwise, we can argue and disagree which is rather pointless (much like the statement above).

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As for the differences Mark found between using a matrix profile and LUT profile, first off, he's making comparisons using the same hardware - both monitor, computer, and colorimeter, so those variables have been eliminated.

We’ve discussed the differences in software! Like that plays no role, seriously.

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The NEC software, as Mark pointed out, is limited by the fact that SpectraView (North America) is unable to make a LUT profile, so it's handicapped to begin with.

Because you (and Mark say so). Other than a personal opinion, there’s zero science yet provided to back this up with respect to this line of product.

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SpectraView and BasICColor each have their own calibration routine that uses DDC to access the internal monitor LUTs, but it's not possible to compare the accuracy of each calibration, because there is not access to the calibration data for both.

Using similar weak logic you and Mark have provided, one could say that NEC who designed both the panel and the software should (will, can, do) provide superior results. Of course I would not suggest that without any evidence but again, one could make up editorial, emotional and provocative statements and suggestions like the discussion presented thus far about LUT based profiles and this line of product.

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Next, in profiling, a 16-bit LUT using CAT02 chromatic adaptation (from CIECAM02) is more likely to give an accurate profile, as determined visually or statistically, than a simple matrix-based profile using ____ (none?, von Kries?, linear Bradford?) chromatic adaptation.

The key word in all the gobbledygook above is “more likely”. Where’s the beef (science) to back this up?

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(AFAIK, SpectraView II doesn't even tell you what, if any, chromatic adaptation it uses. Do you know?)

Do I care? Not really.

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It is widely accepted that matrix based profiles are smaller in filesize, but are somewhat less accurate, whereas LUT based profiles are larger in filesize and generally more accurate (but may sacrifice smoothness).

Define widely accepted by whom and by what degree? It would be very simple to build a better Matrix than LUT profile if so desired. Use a poorer instrument, measure the wrong colors or order etc. So a LUT based profile using a huey would be superior to a $20K spectroradiometer creating a Matrix profile?

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In Mark's case, determining which gives a more accurate profile can be verified visually (which he did!),

Visually? You mean as I suggested (season to taste)? Can’t be that easy.

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Even if the hardware measurement device has some inherent inaccuracy or "offset," it will not affect this statistical comparison. There is no reason to expect that a profile that gives larger errors will somehow be "more accurate" than one that gives small errors...

Accurate defined by who metric and process? Again, more geek gobbledygook. Are you representing the “facts” based on the MSNBC or Fox News slant? I’ll wait for the Scientific America analysis in the meantime if you don’t mind, the match from my NEC to my prints are quite excellent and acceptable. You and Mark can continue discussing how many ICC profiles can dance on the head of a pin.

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NEC claims that the shaper-matrix profiles from SpectraView (North America) are "good enough."  Mark's experience was that for him, they were not.

Mark made the claim without fully testing the products, he made the claim without altering the target calibrations to result in a match with the secondary product which is quite doable, at least many of us here have been able to do so. When he got the results he wanted, he stopped testing the process and provided a conclusion.
« Last Edit: November 14, 2010, 03:22:24 PM by digitaldog » Logged

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« Reply #36 on: November 14, 2010, 03:12:52 PM »
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I'm quite happy with the results.  The display is much closer to the output now. 

Kind of the bottom line here, despite the desire by some to present this as some kind of rocket science and preference for profile type. I’m happy to see you are pleased with the product and the results.
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« Reply #37 on: November 15, 2010, 01:24:01 PM »
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Hogwash and nonsense. The key word above is arguably unless you can point to something other than a personal opinion here. Otherwise, we can argue and disagree which is rather pointless (much like the statement above).

I'm not going to waste much time arguing with you, Andrew, because it is usually pointless, and you seldom provide any concrete science to back up your opinions. You've stated that you don't like math... and this is all about the math.

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It would be very simple to build a better Matrix than LUT profile if so desired. Use a poorer instrument, measure the wrong colors or order etc. So a LUT based profile using a huey would be superior to a $20K spectroradiometer creating a Matrix profile?

This is the first point on which you're completely confused, and this statement shows that you don't understand the fundamentals involved. This issue has nothing to do with measurement accuracy, but everything to do with the non-linearity of the data that you're trying to model. Yes, a LUT-based profile made using a Huey would be better than a matrix-based profile built with data from a $20k spectrophotometer, if the device being profiled has non-linear behavior. In fact, even if the measurement data were exact, without any error, the LUT-based profile would be better, because otherwise you're trying to force a simple model to fit non-linear data. It just doesn't work. At the extreme, it's like trying to find the best straight-line fit through a parabola.

To stick with color management examples, look at printer profiles. Printers (inkjet, press) are clearly non-linear devices. How many matrix-based printer profiles do you know of?  Do you think you could make a better printer profile using a $20k spectrophotometer and a matrix profile than with a $1000 Eye-One Pro and a LUT profile?  It's not gonna happen. The issue is not the accuracy of the measurement data, it's whether or not the function that you're fitting accurately models the real-world, physical phenomenon.

To quote from a  pretty widely accepted source that you're probably familiar with, RWCM(2) p103:

"But matrices are only good for devices with fairly simple tone curves, like scanners and basic CRT-based monitors. For more complex devices, like printers, matrices just don't contain enough information."  "Lookup tables can represent extremely complex devices just by adding more points in the table."

So yea, it doesn't take a rocket scientist to figure out that LUT-based profiles are going to be more accurate than matrix-based profiles for a wide-gamut LCD display, especially when both are made from the same measurement data generated from the same measurement device.  If the non-linearity of the display device is minimal, then the matrix-based profile can do a decent job of approximating the curves. But the LUT-based profile will always be more accurate. It's pretty basic math.

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« Reply #38 on: November 15, 2010, 02:08:10 PM »
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I'm not going to waste much time arguing with you, Andrew, because it is usually pointless, and you seldom provide any concrete science to back up your opinions. You've stated that you don't like math... and this is all about the math.

I think that’s an excellent idea considering you’ve provided no math, evidence or anything but a personal opinion. You are entitled to your opinions, you are not entitled to your own “facts”. You’ve provided no facts. You’ve provided an editorial slant and opinion (European market is arguably more demanding) without an ounce of data to back it up.

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This is the first point on which you're completely confused, and this statement shows that you don't understand the fundamentals involved.

The fundamentals usually require some kind of proof to their validly which you haven’t provided. Nothing stops you from trying at such a point I may consider you have some fundamental information to process. We’re not close to that so far.

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This issue has nothing to do with measurement accuracy, but everything to do with the non-linearity of the data that you're trying to model. Yes, a LUT-based profile made using a Huey would be better than a matrix-based profile built with data from a $20k spectrophotometer, if the device being profiled has non-linear behavior.

Really, only if non-linarity is part of this equation? You sure? You’ve actually done the tests above with the huey and the LUT profile? Using which display product? Just which $20K spectroradiometer are you using for this statement of fact you provided above? Or you’re just pulling more “facts” out of your ass here?

You’ll notice I did not say that the huey would or would not produce a better result (a result that hasn’t been defined mind you), I simply asked you a theoretical question about instruments and the differences between LUT and Matrix profiles, you took the bait and provided yet another non fact based statement. Why should anyone take you seriously?

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In fact, even if the measurement data were exact, without any error, the LUT-based profile would be better, because otherwise you're trying to force a simple model to fit non-linear data.

Better? What’s that mean? A better screen to display match? Less banding? Longer erections? Keep in mind, the discussions here are based upon the use of a SpectraView display system!

We can say that a car with a V8 is better at accelerating compared to a car with a 4 cylinder engine, just like you and Mark like to say a LUT based profile is “better” than a Matrix profile. So much for simplistic ideas, lets look at the analogy further. A V8 with a trailer full of cattle, moving up a 12 percent grade simply will not accelerate better than a small auto with the 4 cylinder going downhill the other direction. But its nice to post simplistic points with no further details or science like “a software product that builds a LUT based display profile is always better than a software product that builds Matrix profiles”. Its as silly a statement as European market is arguably more demanding than the US market. You can believe this if you wish, but don’t expect others here to take such simplistic snippets as factual.

The issue here is that Mark made an equally simplistic post that he feels is fact based as you have, that the NEC software is somehow inferior to the product he used and this inferiority is solely its inability to build a LUT based profile. He got good screen to print match using one product, then stopped testing with the other, ergo, the first product is better. That the 2nd product can produce a screen to print match was simply ignored and worse, the match he got first is attributed to the LUT profile (not the settings of either product). You probably think that’s good science.

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So yea, it doesn't take a rocket scientist to figure out that LUT-based profiles are going to be more accurate than matrix-based profiles for a wide-gamut LCD display, especially when both are made from the same measurement data generated from the same measurement device.  If the non-linearity of the display device is minimal, then the matrix-based profile can do a decent job of approximating the curves. But the LUT-based profile will always be more accurate. It's pretty basic math.

Really? Accurate how and in providing what? So in product A, assuming Mark picked D65 as the white point, you are sure, based on math that the display is emitting D65, that the booth is too? And even if both were (which they are not), that’s a guarantee of a match? The math tells us that we should always calibrate to D65 and we’ll get a match right? Product B is “wrong” because the D65 setting, which isn’t using the same math by all likelihood, is “wrong”? Now suppose Mark was using a different paper, or different viewing condition, or soft proofing what he hopes produces a match using a perceptual table built with different products. This simple measurement data, the math used to build the LUT profile will always produce a visual match? If so, I want to see this in person because it is something I’ve never seen before (and I’ve been calibrating displays since the days Kodak came out with their original “breast pump” Colorimeter circa 1993 or so). In terms of the matrix “better”, read Mark’s post again. He’s saying better by virtue of a screen to print match.

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I told you why I prefer one over the other: the screen to print match was better. As I told you, I used the same calibration settings for both. You asked for the settings: D65, L*, 110 cd/m2. Hope that helps.

You are absolutely positive that product A, with its LUT based profile will always produce a screen to print match when I ask it for D65 and some luminance value because the math is better? And you’re sure that had Mark tried a bit harder to use the SpectraView II software, he could not produce a match, perhaps an equally good or better match? You’re sure of this because of the differences in the profile structure? You’re sure that if I pop a completely different paper into his booth, provide him a profile used to produce that print, and ask him to soft proof it, product A will match and product B will not solely due to a LUT vs Matrix profile? You’ve got the math or you can demonstrate this?

So what software are YOU using to calibrate your NEC SpectraView? What model would that be? I’m just curious because I know a good number of associates with this product line, some actually demanding users who get excellent screen to print matching and I’m concerned they are simply delusional or color blind based on your mathematical based factual science presented here.

By the way, the smartest thing you’ve posted was “I’m not going to waste time arguing” and that the salient points I’ve made here are for lurkers to see that what you and Mark have stated thus are not to be taken seriously. Don’t think of this as an argument. When someone tells you they are not going to waste time arguing, its often a sign that they see they have done a piss poor job thus far of making a valid point and that someone who is “arguing” is simply calling them on their posted nonsense.

What you should consider doing, instead of making up web forum opinion pieces, is ASKING NEC why they don’t make a LUT based profile (they do discuss the time it takes to do so and all the measurements necessary). You suppose they are unable to do this? Or maybe, unlike you and Mark, they actually understand how their products, software, and math, along with sound scientific testing provided them with a reason not to.
« Last Edit: November 15, 2010, 02:10:55 PM by digitaldog » Logged

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« Reply #39 on: November 15, 2010, 05:13:14 PM »
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I think that’s an excellent idea considering you’ve provided no math, evidence or anything but a personal opinion.

Actually, I did, but you're not capable of conceptualizing and solving Gedankenexperiments or word problems and you feel that all "math" requires an equation to be handed to you, which you may or may not understand. The concepts are quite clear and are indisputable - unless you don't understand them. And as usual, that's the time you start spewing venom, vitriol and character assassinations instead of sticking to the facts.  The quotes from RWCM on the differences between matrix-based profiles and LUT-based profiles were pretty straight-forward.

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You’ve provided an editorial slant and opinion (European market is arguably more demanding) without an ounce of data to back it up.

Fact: I stated that each NEC monitor in this series sold in Europe is individually certified. They are not individually certified in North America.

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What you should consider doing, instead of making up web forum opinion pieces, is ASKING NEC why they don’t make a LUT based profile (they do discuss the time it takes to do so and all the measurements necessary). You suppose they are unable to do this? Or maybe, unlike you and Mark, they actually understand how their products, software, and math, along with sound scientific testing provided them with a reason not to.

Mark asked NEC (Will) that very question.

Will told Mark that they don't do it because:

"While it is true that LUT based display profiles can be an advantage over simple matrix profiles on certain types of displays that have very non-linear additive color properties (i.e. they do not behave Grassmann’s law of additive color well), the IPS panels used on the PA series and internal 3D matrix correction make the display’s additive color response very linear. This can be represented very accurately by a simple matrix."

"At the end of the day, SpectraView does not support LUT profiles." "you could always try profiling the display using a 3rd party package that does support LUT profiles and see if you get any improvement."

He did. And he did.

Exactly as Mark said over and over again in his posts before he quit this thread, the whole argument turns on whether the display is truly linear. When tested, this wide-gamut display is not perfectly linear.  So the matrices approximate the true curves, which takes us back to the previous post. LUT wins.

The fact remains that NEC sells the same monitor in Europe with far more sophisticated software than SpectraView, feature by feature. So for whatever reason, NEC gives European users the capability of building LUT-based, CIECAM02-capable profiles, in addition to simple matrix-based profiles, and they don't offer that to North American users. You still haven't offered your explanation for why that is. Instead, you sound like a NEC shill, defending them 'till death do you part, regardless of the evidence. Maybe it's time for full disclosure, because you sound anything but objective. Sorta like when you're talking about... awe, forget it.

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