Luminous Landscape Forum

Raw & Post Processing, Printing => Colour Management => Topic started by: rasworth on April 25, 2011, 01:08:18 pm

Title: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: rasworth on April 25, 2011, 01:08:18 pm
Read the targets for Red River UltraProSatin with both i1Pro-uvcut and i1Pro-normal.  The paper isn't as loaded with OB's as most rc types, but still has enough to trip the "Correct for Optical Brightener" check box in ProfileMaker Pro 5.10.  Attached is the spectral profile for bare paper from both instruments, uncut on the right.

After measurement in i1Profiler I did a data analysis comparing the two scanned measurement files - it showed a definite difference, primarily in the lighter tones, with a 2.23 delta e for the 10% highest deviating patches.  All seemed consistent to this point.

Created two identical parameter profiles with the two measurement sets, ran one test print thru both, and visually compared.  I can see no difference between the two prints - more test prints and measurements would be required to make sure, but my initial conclusion is i1Profiler is doing some sort of uv detection/compensation, and that at least for this paper the two i1Pros work equally well.

Question to the experts - other than always creating two profiles and comparing, when do you choose one i1Pro over the other?  I guess another way to ask the question is why not always use the uvcut version?

Richard Southworth

Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: terrywyse on April 25, 2011, 01:21:10 pm
As an expert, I never use an i1Pro except in the pressroom and on displays.....I use an iSis and capture both sets of data and then compare....I'll then decide to use one or the other "filtered" dataset or take an average of both.

In my opinion, using two different instruments, which would necessarily be the case with the i1Pro since you can't change filters, is already introducing a variable or "uncertainty" about these findings. You're better off with something like a DTP70 or iSis where you're using the same instrument for a comparison like this, with the DTP70 showing the effects of different *filtration* while the iSis would show the effects of two different *illuminants*.

Also, if you're using relative colorimetric rendering for such a comparison, I think the effects of OBAs would largely be factored out since it's essentially "zeroing out" the paper white during conversion.....absolute colorimetric would more likely show these differences since the paper white disparity would be imposed on the final rendering.

Just sayin'  ;)

terry
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Ernst Dinkla on April 25, 2011, 02:18:29 pm
The Red River Ultra Pro Satin is just one quality of an FBA paper.

It is represented here with the blue spectral plot, the Red River Artic Polar Satin is in red and the non-FBA  Canson Rag Photographique is in green. Yellow is a plot for a Baryte tile, for reference. Measured with an Eye 1 Basic UV+.

ArgyllCMS more or less cuts the FBA effect with a straight line from the high point within 650-700 Nm through the lowest point between 450-520 Nm to simulate an UV-cut spectrometer measurement. http://www.imaging.org/IST/store/epub.cfm?abstrid=22190  Actual algorithm used in ArgyllCMS has been slightly changed.

The Eye 1 Pro UV+ is basically an illuminant A spectrometer, FBA effect is not that great. The UV-cut version does not measure below 400 Nm.


met vriendelijke groeten, Ernst

New: Spectral plots of +250 inkjet papers:

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: rasworth on April 25, 2011, 02:20:00 pm
I removed two previous posts, they were  not well thought out.

My question had to do with the use of i1Pros, I did not ask if there were better methods of measuring profiles.  Therefore IMO your response was not helpful.

Richard Southworth
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: terrywyse on April 25, 2011, 02:20:03 pm
Mileages may vary of course.....but frankly I've not had any obvious OBA correction issues since switching to MonacoPROFILER some years back and most recently (4-5 years?) getting the iSisXL....but this was a farily common occurence with PM4/5. All I know is that I would put a spectro to my head and shoot myself if I had to use an i1Pro on a daily basis....but that's neither here nor....there.  :)

On the other hand, I tend to be in the inkjet proofing world and OBAs are not quite the issue as they might be in the photographic world.....we mostly have good medias available without "glaring" amounts of OBAs.....so there you have it.

Regards,
Terry
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Scott Martin on April 25, 2011, 05:07:32 pm
Really short response: always use the UV Cut - unless you taking spot measurements where you want to use the OBA effects.
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: rasworth on April 25, 2011, 05:28:55 pm
Scott,

Any advice about which to use for monitor calibration/profiling?  I have read conflicting opinions as to advisability, I've had no problems using the normal i1Pro, more just curious about in the field experience.  If the uv filtering is done on the lamp, than I would think there would be no effect on display profiling, other than the instrument calibration still uses the internal light source.

Richard Southworth
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Scott Martin on April 25, 2011, 05:36:22 pm
I've seen no effect for display profiling, but I have to admit I prefer a great colorimeter to a spectro for display calibration, along with software that performs an iterative calibration process.
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: jaapb on April 26, 2011, 01:49:05 am
I've seen no effect for display profiling, but I have to admit I prefer a great colorimeter to a spectro for display calibration, along with software that performs an iterative calibration process.

Scott,

For wide-gamut displays you are probably better off with a spectrophotometer.
http://www.argyllcms.com/doc/WideGamutColmters.html

Jaap
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Jalok on April 26, 2011, 08:56:22 am
Created two identical parameter profiles with the two measurement sets, ran one test print thru both, and visually compared.  I can see no difference between the two prints - more test prints and measurements would be required to make sure, but my initial conclusion is i1Profiler is doing some sort of uv detection/compensation, and that at least for this paper the two i1Pros work equally well.

I have done some comparison tests between i1Profiler and ProfileMaker profiles built from the same measurement data taken by an i1Pro non-UVcut. The conclusion is i1Profiler surely has something like PM's optical brightener compensation ("Correct for Optical Brightener" function). For two different and highly OBA charged papers (one matte another rc), and for two different ink sets (OEM and non-OEM Canon CLI-8 inks), i1Profiler with null value for "neutralize gray" parameter gave me identical or very very similar softproofing and printed results regarding to OBA compensation as PM did with its "Correct for Optical Brightener" function enabled. Also, by experimentation there were no i1Profiler settings which could reproduce the yellowish results printed from a PM non-COB profile. So I concluded the i1Profiler lack of a on/off brightener compensation should not be missed, unless someone needs non-COB results for special purposes. Should be said I only used perceptual rendering for the referred softproofing and printing comparisons. Maybe i1Profiler OBC-like feature does not work with the other rendering intents.
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Scott Martin on April 26, 2011, 09:23:35 am
Scott,For wide-gamut displays you are probably better off with a spectrophotometer.
http://www.argyllcms.com/doc/WideGamutColmters.html

The Spyder3 is the exception to this rule. It's unusual 7 sensor design make it unusually well qualified for calibrating wide gamut displays. In fact, it's able to measure subtle low light differences better than a common spectro like the EyeOne. The shadows come out exceptionally well. Try a comparison for yourself! Whatever device you use, make sure you use an iterative calibration process - I find that goes a long way towards achieving smooth gradations.
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: jaapb on April 26, 2011, 02:04:56 pm
The Spyder3 is the exception to this rule. It's unusual 7 sensor design make it unusually well qualified for calibrating wide gamut displays. In fact, it's able to measure subtle low light differences than a common spectro like the EyeOne. The shadows come out exceptionally well. Try a comparison for yourself! Whatever device you use, make sure you use an iterative calibration process - I find that goes a long way towards achieving smooth gradations.

Thanks Scott,

I wasn't aware of that, I don't have a Spyder3 (yet) maybe in the near future I will do the comparison.

Jaap
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Ernst Dinkla on April 26, 2011, 04:11:24 pm
The Spyder3 is the exception to this rule. It's unusual 7 sensor design make it unusually well qualified for calibrating wide gamut displays. In fact, it's able to measure subtle low light differences better than a common spectro like the EyeOne. The shadows come out exceptionally well. Try a comparison for yourself! Whatever device you use, make sure you use an iterative calibration process - I find that goes a long way towards achieving smooth gradations.

AFAIK, a colorimeter 3 to 7 LEDs / sensor combination still has to be adapted for that wider gamut RGB emission and in that adaption it will not be right for a normal gamut. With several display gamut sizes in use now and deviations between individual colorimeters it has to be seen whether the Spyder 3 is always correct. ArgyllCMS has a compensation setting for colorimeters. It is correct that a colorimeter is better at low light differences than a spectrometer.

It is better explained here:
http://hoech.net/dispcalGUI/


met vriendelijke groeten, Ernst


New: Spectral plots of +250 inkjet papers:

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Ernst Dinkla on April 27, 2011, 03:58:12 am
So I concluded the i1Profiler lack of a on/off brightener compensation should not be missed, unless someone needs non-COB results for special purposes. Should be said I only used perceptual rendering for the referred softproofing and printing comparisons. Maybe i1Profiler OBC-like feature does not work with the other rendering intents.

The common conclusion in all the forums seems to be that UV-cut profiles (in what way they are created doesn't matter here) make prints that are generally more pleasing to look at under varied consumer lighting conditions. I guess that does not include going through photo albums on the porch. What surprises me more is that 99% of RC papers has FBA content, 20% deliver b -10 brightness. A lot of other paper qualities rely on it too. We do not get other papers (excluding the ones for archival reasons) and we seem to like what actually warps colour management, a profile made for a "neutral" paper while the paper varies from b -2 to -10. And I know from practice that even indoors FBA effect is seen with RC papers. More subtle profiling features like adapting the grey axis to paper white starts in that case with data that is already compromised. I am actually not questioning the consumer's eye sight or the experts' vision on it but question why this practice isn't discussed as being warped CM. The more I read and learn about CM, the more I get the impression that it isn't a hermetic system in its fundamentals (for example: Delta E is not the same throughout the space) and CM practice saws on the other legs of the stool.


met vriendelijke groeten, Ernst


Dinkla Gallery Canvas Wrap Actions for Photoshop

http://www.pigment-print.com/dinklacanvaswraps/index.html

Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: PhilipCummins on April 27, 2011, 07:53:46 am
Any advice about which to use for monitor calibration/profiling? I have read conflicting opinions as to advisability, I've had no problems using the normal i1Pro, more just curious about in the field experience.  If the uv filtering is done on the lamp, than I would think there would be no effect on display profiling, other than the instrument calibration still uses the internal light source.

From what I've read either UV-cut or No-Filter works fine for display calibration & profiling, the filter itself only affects the internal i1Pro light source, the central reading aperture is clear on both versions.
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: rasworth on April 27, 2011, 09:22:22 am
Yes, but ...  I've read opinions both for and against.  My only concern would be the effect of the uv filter upon calibration of the i1Pro just before monitor profiling.  I don't know how sharp the uv filter is, i.e. does it affect some of the visible blues, and therefore might impact the accuracy of calculating the blue primary.  I would think it would be a second order effect at worst, but I haven't really tested.

I attached the spectrum plot of my display white (measured with a normal i1Pro), running at 5500K.  It pretty well covers the sRGB gamut, a wider gamut display might have stronger blues farther down in the spectrum.  If the uvcut instrument mis-reads too many slices at the blue end because of inaccurate calibration it could affect the results.  Probably just of academic interest, most will use either a colorimeter or a basic i1Pro for monitor calibration/profiling.

Richard Southworth
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Ernst Dinkla on April 27, 2011, 09:46:19 am



the central reading aperture is clear on both versions.

Not according to this article:

http://rmimaging.com/information/Chromaxion_Issue_1.pdf

It could still have a compensation for that blue or that blue may not affect the display calibration but it is not clear.


met vriendelijke groeten, Ernst


New: Spectral plots of +250 inkjet papers:

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Scott Martin on April 27, 2011, 12:00:07 pm
Richard you've got me thinking, so I've been doing a fresh round of testing this morning with my UV Cut i1 and Spyder 3 with i1Profiler, DispCal, Color Eyes Display Pro, and Spyder3Elite. I'm using i1Profiler for statistical analysis and my evaluation image in Photoshop with and without soft proofing for visual analysis. 

I'm pretty stunned with what I'm seeing out of i1Profiler so far. Not only does the process take less than 2 minutes (!!) but the shadows and smoothness are incredible, rivaling even DispCal's hour long calibration process. i1Profiler's QA analysis reports lower Average Delta E variations with i1Profiler's calibration than the others. I've been frustrated with shadow detail from the i1 Pro in the past but i1Profiler is doing a better job than I've seen with previous solutions.

I'm continuing to test as the number of possible combinations is quite numerous. For example, can the results of a colorimeter be equal to that from i1P/i1Pro when a DispCal colorimeter adjustment is applied? How do all of these results average when we include a large number of display into this testing? It will take time to answer these questions.

It's pretty clear at this point that if you already own a UV Cut i1Pro and i1Profiler, I'd say that's an excellent single solution that you could feel really good about using for calibrating not only printers but displays (small and large gamut) as well. It's simple, fast, and the results are visually and statistically fantastic in comparison to many of the leading options.

For those that don't own an i1Pro and I1Profiler, there are several excellent options from Spyder3Elite (best value, easy to use, cost effective), to ColorEyesDisplayPro and BasICColor (more geeky and more expensive) and lastly DispCal (super geeky but supports lots of devices). And of course there are proprietary solutions like those from NEC, EIZO and Barco. What a complicated landscape this has become!
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: VitOne on April 27, 2011, 12:01:34 pm
I am not an expert but I'll give you my two cents.

I don’t own an i1Pro with UV filter, but I own a ColorMunki. I never understood how similar this 2 instruments are, I read many different opinions. I also made a “comparative test” in the past: http://www.luminous-landscape.com/forum/index.php?topic=50214.0

I made some profile, using Argyll and starting from the same 2000 patches, with the i1Pro (with and without FWA compensation) and ColorMunki.

I used a GrafiLite Mode (Ott-Lite, see this: http://photo.net/digital-darkroom-forum/007Ue2) and natural solar light to look at the prints (I printed a test image with RelCol and AbsCol from Photoshop with BPC for each profile). I think that the best prints where the one made from the i1Pro –f profile (Argyll FWA compensation). They looked more neutral that the one from the ColorMunki and the one from the i1Pro without FWA, in the BN I saw no particular cast in the –f profile.

I did this simple and stupid test.

This is the test image:
(http://www.pctunerup.com/up/results/_201104/20110427142109_CompareOriginale.jpg)

Made with Canon 1D Mark III, 24/70 2,8, DNG profile using CC Passport. Light from the window.

Image is ProPhotoRGB, 16bit, opened in Photoshop.

Print made with an Epson 790, OEM Ink, Hanhemuhle FA Baryta paper.

The paper has some OBAs, as you can see using this online plotting tool: http://www.pusztaiphoto.com/articles/printing/spectrums/webchart.aspx

The upper part is a print made with i1Pro, ArgyllCMS and FWA compensation ON (for D50 illuminant).

The lower part is a print made with the ColroMunki. The profile, the test chart, all the setting where the same. Both the profiles have very good DeltaE 2000, max is below 1,5 (and average is in both profile below 0.6), i1Pro profile is a little bit better comparing numbers.

Here you can see the BW part of this image “averaged” with Photoshop.

(http://www.pctunerup.com/up/results/_201104/20110427173946_CompareOriginale2.jpg)

The image that you see here is in sRGB space, the reported values are from the original file (ProPhotoRGB).
As you can see my impression of a bluish cast in the CM profile is confirmed by the data. I don’t know how the i1Pro UV Cut would behave, but asking several people I trust, I always got suggestion about buying an instrument with no filter, so that the “profiling program” could care of OBAs. Graeme Gill (ArgyllCMS author) recommends to use non-filtered instruments: http://www.argyllcms.com/doc/FWA.html
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Scott Martin on April 27, 2011, 12:19:02 pm
Good testing there, but so many more variables to continue testing! I'd also like to see some spot spectro measurements of those grays. You've shown the need for OBA/FWA correction, but haven't tested hardware via software solutions. Sure Graeme is going to suggest an unfiltered device, particularly because his solutions provide software based corrections. But what about i1Profiler that doesn't have a software based solution? I'd like to see a comparison of your UVin Argyll profile to a UVex i1Profiler profile. And another comparison of the two apps comparing both the Perceptual and Relative Colorimetric intents. I'd like to see that, just for starters. :-]

For the sake of the OP, I think all the evidence is showing that his UVCut/i1Profiler purchase was an excellent one that he can use for nearly all of his work.

If we were to ask "What's the right solution for me?" I'd think we'd have to ask who "me" is. If "me" is a demanding print and image maker with a thirst for travel we might come up with one solution. If "me" is a retired amateur color scientist with a thirst for hours of statistical analysis we might have a different set of solutions. Some of us just have to find that sweet spot in the middle.


Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Alan Goldhammer on April 27, 2011, 12:40:33 pm

The image that you see here is in sRGB space, the reported values are from the original file (ProPhotoRGB).
As you can see my impression of a bluish cast in the CM profile is confirmed by the data. I don’t know how the i1Pro UV Cut would behave, but asking several people I trust, I always got suggestion about buying an instrument with no filter, so that the “profiling program” could care of OBAs. Graeme Gill (ArgyllCMS author) recommends to use non-filtered instruments: http://www.argyllcms.com/doc/FWA.html
As I reported in another thread, the exact same thing happened to me when I used Argyll to do a profile using CM of Ilford Gold Fiber Silk.  When I first opened up the profile in PS to look to see the effect I was rather shocked and thought I did something wrong.  I did a second profile this morning using a smaller number of patches and the same thing, blue cast to the profile in PS.  Thing is though, it is a good profile when I print a test image.  However, I'm not sure how to get around the blue cast if I want to use it for soft proofing.  My understanding is that the -f switch in Argyll has no impact on CM profiles.  I guess I can check it easily enough with my smaller patch set.  Also, you can get a much better data set of papers at Ernst Dinkla's site:  http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Scott Martin on April 27, 2011, 12:57:06 pm
Right - the blue cast when soft proofing. Add that to the list of reasons to measure UVex for fine art/ pleasing color situations.

What about metallic silver halide papers that don't contain and OBA/FWAs? Why to they profile better from UVex measurements? I keep pairs of devices (UVex and UVin) around for different purposes but I'm finding that real world testing suggests that UVex measurements are the way to go the majority of the time again in fine art/ pleasing color environments.
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Alan Goldhammer on April 27, 2011, 01:00:55 pm
Right - the blue cast when soft proofing. Add that to the list of reasons to measure UVex for fine art/ pleasing color situations.

What about metallic silver halide papers that don't contain and OBA/FWAs? Why to they profile better from UVex measurements? I keep pairs of devices (UVex and UVin) around for different purposes but I'm finding that real world testing suggests that UVex measurements are the way to go the majority of the time again in fine art/ pleasing color environments.
I guess the ArgyllCMS software cannot get rid of the blue cast; I'll have to post and ask the question.  I do know that the ColorMunki native software for doing profiles does not give the cast.  Ilford Gold Fiber Silk has some OBAs in it but not that much as the spectral curve does not show a big bump that some of the others do 440 nm.  I have not profiled a non-OBA paper with Argyll to see what happens and whether there is a blue cast or not.
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Alan Goldhammer on April 27, 2011, 08:28:35 pm
I solved the problem of the blue cast in the profile.  It was generated by creating the profile for viewing under D65 rather than D50 and only shows up when you have Simulate Paper Color checked (which you need to do).  When you prepare a profile under the default of D50, there is no problem.
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: PhilipCummins on April 28, 2011, 04:04:37 am
Not according to this article: http://rmimaging.com/information/Chromaxion_Issue_1.pdf
It could still have a compensation for that blue or that blue may not affect the display calibration but it is not clear.

Note the article refers to the Spectrolino filters that they tested, which they "assumed" would be the same as the i1Pro ones which is incorrect. If they were serious, they could have simply removed the i1Pro filter head for analysis. My own examination (since I have both a UV-Cut and No-Filter i1Pro here) is what I said earlier - the centre aperture is clear, while the outer ring has either an additional purple-blue filter that is present (for UV-Cut) or not present (No-Filter). IMHO X-Rite just makes the same i1Pro, then programs the firmware and adds the filter (or not) as required. I'm due to do some tests to see if switching the No-Filter for the UV-Cut filter simulates UV-Cut appropriately which means you essentially can get both readings from a single i1Pro, however slightly less conveniently vs an Isis.
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: PhilipCummins on April 28, 2011, 04:17:15 am
My only concern would be the effect of the uv filter upon calibration of the i1Pro just before monitor profiling.  I don't know how sharp the uv filter is, i.e. does it affect some of the visible blues, and therefore might impact the accuracy of calculating the blue primary.  I would think it would be a second order effect at worst, but I haven't really tested.

It doesn't since the filter only affects the internal i1Pro light source. Since you use a dark measurement to calibrate the i1Pro in Argyll the entire UV-vs-No-UV issue is avoided as the lamp isn't used to calibrate via the white tile. Other people have mentioned that calibration of monitors with and without the filter has made no difference so I'm inclined to believe them from what I know (owning both & having checked the filters out). I have to admit it would be nice if X-Rite just packaged both filter heads with each i1Pro, can't cost that much to include it...
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Ernst Dinkla on April 28, 2011, 05:26:04 am

I have to admit it would be nice if X-Rite just packaged both filter heads with each i1Pro, can't cost that much to include it...


I did wonder about that too. 5 Euro at most in production costs. Make it 50 Euro and it would still sell. If it is just the cone + glass disc inside there.

If an Eye 1 goes back to X-Rite for recalibration it would surprise me if they cleaned that cone and glass disc. More likely the part is replaced.

met vriendelijke groeten, Ernst

New: Spectral plots of +250 inkjet papers:

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Ernst Dinkla on April 28, 2011, 05:33:17 am
Note the article refers to the Spectrolino filters that they tested, which they "assumed" would be the same as the i1Pro ones which is incorrect.

The cure however works accordingly. It will be hard to measure the Eye 1 filter without taking cone and glass apart. Taking the cone off is easy.


met vriendelijke groeten, Ernst

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Ethan_Hansen on April 29, 2011, 07:20:39 pm
We finished measuring a range of monitors with over 60 different sensors. A synopsis is here on LuLa (http://www.luminous-landscape.com/forum/index.php?topic=53825.0) while the full article is on our site (http://www.drycreekphoto.com/Learn/Calibration/MonitorCalibrationHardware.html). As part of this exercise, we looked at 10 i1-Pro units. Four were UV-cut, six were not. There was no statistically significant difference between them in terms of emissive measurements. That is what you would expect, since the UV-cut model adds a yellow filter in front of the measurement lamp to cut the UV component of the light.

On the question of which version to buy for printer profiling, it depends on the software you use. Neither Monaco Profiler nor i1Profiler have software-based optical brightener algorithms for general measurements. i1Profiler has the OBC module, but this only works with the i1iSis. Profiles made from many papers with high levels of optical brighteners using either i1Profiler or Monaco can exhibit yellow casts to highlight areas where the software attempts to compensate for the blue paper tint read by the spectro. For either of these products, your best bet is to use the UV-cut i1.

Now, if you use either iMatch, ProfileMaker, BasICColor Print, Argyll, or any other profiling software that has fluorescent brightener compensation algorithms, I would opt for the normal, no-cut version of i1. All these products usually do a good job of detecting and compensating for optical brighteners. I do not understand why X-Rite dropped these algorithms from i1Profiler. Perhaps they felt the iSis provided the correct way of handling UV - and it does - and did not want to settle for an approximation that only worked 95+% of the time.

Another problem that crops up occasionally with the UV-cut i1-Pro is that X-Rite's software reports measurement values for wavelengths below 400nm. Who knows where these readings come from. The lamp filter effectively cuts off all light emission below 400nm. Nevertheless, a CGATS measurement file contains readings at 380 and 390nm. Most of the time these values are a fairly flat line from 400nm and down. Occasionally, however, you see huge spikes in the 380 or 390nm readings. This behavior appears with most legacy GMB instruments - files from a UV-cut icColor show the same thing. If the short-wavelength readings are sufficiently high, the profiling software happily introduces a color cast to highlight areas.

Making matters worse, this behavior is unpredictable. The instrument is measuring sensor noise at these wavelengths and the data files contain the results of X-Rite's extrapolation algorithms. Why X-Rite does not cut all data below 400nm for UV-cut instruments I can't say. I also do not know if this problem continues to i1Profiler. Measurement data files still show bogus short-wavelength readings but I do not know if the software ignores these data.
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: rasworth on April 29, 2011, 10:12:04 pm
Ethan,

As stated earlier, I have an older (2nd generation) i1Pro basic and a brand new i1Pro uvcut.  Using Measure Tool I sampled a bare spot on Museo Silver Rag with both instruments, the spectrum pictures are attached.  Two questions:

1. Apparently I obtained a more well-behaved reading with the i1 uvcut, 380-400mm didn't spike up.  Will the remaining inaccuracies affect my profile generation, within i1Profile?  I'm asking because I did use the uvcut for the measurement scan, and all appears well.  Not sure why I chose it other than it was the newer toy, after reading your analysis I should have used the basic unit on such a well behaved paper.

2. Per my first post, I created two profiles on another paper with ob's, one with the i1basic and one with the i1uvcut, which yielded to my eyes identical results on test prints.  How can you be sure i1Profiler is not applying some degree of ob compensation?

Thanks for your detailed work,

Richard Southworth
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Scott Martin on April 29, 2011, 10:15:31 pm
Now, if you use either iMatch, ProfileMaker, BasICColor Print, Argyll, or any other profiling software that has fluorescent brightener compensation algorithms, I would opt for the normal, no-cut version of i1. All these products usually do a good job of detecting and compensating for optical brighteners.

That compensation is only for the Perceptual intent and problems can occur when using the other intent. I'd argue that there's merit in using UVex data even for these app as well.

I do not understand why X-Rite dropped these algorithms from i1Profiler. Perhaps they felt the iSis provided the correct way of handling UV - and it does - and did not want to settle for an approximation that only worked 95+% of the time.

Maybe because it was an imperfect band-aid and they're rather work towards a more universal solution? The iSis approach is totally different and the variable nature of it is pretty cool. I suspect there's more to come on this front.
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Scott Martin on April 29, 2011, 10:18:25 pm
I created two profiles on another paper with ob's, one with the i1basic and one with the i1uvcut, which yielded to my eyes identical results on test prints.  How can you be sure i1Profiler is not applying some degree of ob compensation?

Direct discussion with the developers confirms there is no OBA compensation. The difference can be visually slight but becomes more obvious when you a) compare papers with huge amounts of OBAs and b) when these prints are viewed under daylight with lots of UV and c) when you soft proof these files (which uses the other side of the profile). There is a difference to be seen but it won't blow your socks off.
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Ethan_Hansen on April 29, 2011, 11:15:51 pm
Richard - Your graphs show exactly what happens with X-Rite UV-cut instruments. The i1Basic/no-cut plot on top shows the reflectance from the paper dropping off at wavelengths below - swagging it from the picture - 460nm or so. That's a typical paper spectrum for OBA-free stock. The UV-cut i1 plot shows a slight increase in measured intensity at 380 and 390nm. That's X-Rite's screwy algorithm at work rather than actual data. We have seen cases where the reported intensity exceeds 100% at 380nm.

[Quick digression: We build profiles for photo labs, re-profiling at regular intervals. Part of the service we provide is monitoring printer performance. We have tracked some printers for nearly a decade, so we have a good baseline to compare to. We also track the paper measurements. This catches the occasional bad emulsion batch and has been fed back to the paper manufacturers for performance analysis.

We tried using a UV-cut iCColor and our data integrity checks flagged the occasional paper white as being off. Our targets contain a number of repeat color patches, including white. The majority of the oddball readings occurred on some but not all of the white patches. Our first thought was a gross non-uniformity on the paper itself. Measuring on a Spectroscan disproved that idea and remeasuring on the UV-cut iCColor gave non-repeatable results. Finally we figured out that the short wavelength measurement data were a guess rather than reality. Conversations with GMB engineers (this was pre-X-Rite merger) confirmed our suspicions.]

If you are using a standard target with only one white patch, a white patch that reads as artificially blue will throw your profile off.

Scott: I agree that the iSis solution with the OBA compensation routine is very cool. Were it not such a hack and PITA to implement on a volume basis that would be better still. Nevertheless, there is a place for software-based OBA compensation. The original method GretagMacbeth implemented in ProfileMaker V4.something was good, the refinements in V5 made it better.

Yes, the iSis OBC method works better in most instances (except for some pathologically OBC-laden papers where the OBC target contains no neutrals). That is no reason to leave non-UV cut i1Pro owners with no means of compensating for OBAs or for those working in real-world environments where printing a second target and evaluating it is not in the cards.
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Scott Martin on April 29, 2011, 11:27:13 pm
Your graphs show exactly what happens with X-Rite UV-cut instruments.

All of them? Or are we just talking about EyeOnePros?

That is no reason to leave non-UV cut i1Pro owners with no means of compensating for OBAs or for those working in real-world environments where printing a second target and evaluating it is not in the cards.

I think the reasons will be revealed in good time. For the time being one might suggest that the improvements in profile quality outweigh the minor discrepancies seen without OBA correction. Others here have stated they can't even see these differences for example. And one might suggest that pros will always need to ability to generate both UVin and UVex measurements.
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Ernst Dinkla on April 30, 2011, 06:28:38 am
Direct discussion with the developers confirms there is no OBA compensation. The difference can be visually slight but becomes more obvious when you a) compare papers with huge amounts of OBAs and b) when these prints are viewed under daylight with lots of UV and c) when you soft proof these files (which uses the other side of the profile). There is a difference to be seen but it won't blow your socks off.

Within the condition of the thread subject: i1Profiler as the software an Eye 1 UV-cut model would be more suitable. In a sense so far it has been developed for that version of the Eye 1. You sketched the limitations of that development goal if the Eye 1 is the hardware to be used.

The illumination A lamp of the Eye 1s in general already reduces the FBA effect, a SpectroCam without UV filter delivers more. What exactly the iSis modes have for illumination is something I'm curious about, without UV light does it deliver true measured numbers from 380 to 730 NM, is the UV light going to shorter wavelengths than any other X-rite model?

Ethan sketched the other suitable combinations of profile creators and hardware and in that case the Eye 1 Basic without a UV filter will be more versatile and should be more accurate on the blue to UV range in all cases. Even more compared to a ColorMunki that is measuring a shorter range of wavelengths than the Eye 1 UV-cut but isn't shy to fill the wider gaps with arbitrary data.


met vriendelijke groeten, Ernst

New: Spectral plots of +250 inkjet papers:

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm





Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: rasworth on April 30, 2011, 09:20:35 am
Scott,

Yes, I understand the AnTOBn side of profiles, I compared soft-proofs as well as test prints of the differently generated profiles of a paper with OBs.  I can buy that the particular paper I used (RR Ultra Pro Satin) doesn't have huge amounts of OBs and therefore i1Profiler with no OB compensation might still produce similar results between the two profiles, if I have the energy at some point I'll do a dual scan of one that's loaded.

In the mean time I believe I will use the i1Pro basic for "good" papers and the uvcut version for others, seems to be the most logical course with what we know about i1Profiler.  I also have PMP5, but I really do like the profiling controls in i1Profiler, particularly the contrast, enables one to better tailor profiles to taste, particularly with fine art papers.

Richard Southworth


Richard Southworth
Title: Re: i1Profiler - i1Pro-uvcut vs. i1Pro-normal
Post by: Jalok on May 03, 2011, 08:59:08 am
The common conclusion in all the forums seems to be that UV-cut profiles (in what way they are created doesn't matter here) make prints that are generally more pleasing to look at under varied consumer lighting conditions. I guess that does not include going through photo albums on the porch. What surprises me more is that 99% of RC papers has FBA content, 20% deliver b -10 brightness. A lot of other paper qualities rely on it too. We do not get other papers (excluding the ones for archival reasons) and we seem to like what actually warps colour management, a profile made for a "neutral" paper while the paper varies from b -2 to -10. And I know from practice that even indoors FBA effect is seen with RC papers. More subtle profiling features like adapting the grey axis to paper white starts in that case with data that is already compromised. I am actually not questioning the consumer's eye sight or the experts' vision on it but question why this practice isn't discussed as being warped CM. The more I read and learn about CM, the more I get the impression that it isn't a hermetic system in its fundamentals (for example: Delta E is not the same throughout the space) and CM practice saws on the other legs of the stool.

Thanks, Dinkla, for your valuable words. I agree with all of them. But I like to add a variable that is absent to many of us who write in this forum. As I live in a country that has the highest importing/duty taxes around the world (around 80% excluding the shipping costs), it's almost always very difficult and very expensive to import good low-OBA papers. And as I don't sell my printings and I'm not a professional photographer, only a few printing jobs justify the time and money expenses in purchasing these good papers. So most the time I have to live with the best I can find in domestic market. You could imagine how valuable your spectral plots for inkjets papers are to me, which I was aware of only a few weeks ago, as they help to narrow choices on the first round. Thanks again!