Custom Offsets with the i1 Display Pro OEM in Lightspace DPS

June 8, 2016

Learn how using Custom Offsets with the i1 Display Pro OEM can turn this inexpensive colorimeter into a reference meter you can trust.


Series
Optimizing the i1 Display Pro OEM in Lightspace: Part 2

How to Use Custom Offsets with the i1 Display Pro OEM to Radically Improve Its Results

Earlier this year a family member underwent a Bone Density test, to measure the strength (or brittleness) of their bones. The result was interesting because they couldn’t actually make any decisions based on a single result.

The result told my family member that their bone density was ‘slightly below average’. But since they never had this test done before there was no way to know if this was a long-term improvement or a more recent degradation? This first test was merely a baseline.

Going forward, they’ll take annual bone density tests to see the trendline. And then the trendline will give them actionable information.

Using Generic offsets that ship with our colorimeters is like that Bone Density test

The reports we generate in Lightspace (and CALman) using the generic offsets are not absolute values that tell us, “Yes this display must be recalibrated”.

Why? Because we can’t trust the raw Delta E’s using those generic offsets—they’re too generic!

The generic offsets that ship with Lightspace and are available to use with the i1 Display Pro OEM
When you use the ‘Calibration Settings’ pull-down, you’re applying generic offsets that are pre-loaded on your colorimeter and are available to use within Lightspace and CalMAN. For precise readings, we need custom offsets – set elsewhere in Lightspace.

A major resource I’ve been relying upon throughout this Profiling 101 Series is Flanders Scientific. They were very happy to share the Generic Offsets you should use for their full line of displays. I’ll be happy to update this Insight with the proper pull-down selections for other lines of reference displays if you want to leave them in the comments.

Flanders Scientific Generic Offsets, i1 Display Pro:

Wide Gamut CCFL: LM-2461W, CM240

RGB LED: CM171

White LED: BM210, BM230, BM240, BM090, AM420, AM550, CM320TD, CM420TD, CM500TD

OLED: AM250, CM250, DM250, CM172

The Profile results generated from generic offsets are merely baseline measurements.

If you’re using a generic offset then you need to do multiple Profiles over time and compare the relative drift as the display ages.

Stated again: Using the profiles that ship on your colorimeter (including the i1 Display Pro OEM) you need to ignore the raw Delta E values and only rely on how those values drift over time in comparison to an initial baseline Profile.

The best way to create your baseline Profile is immediately after your display is professionally calibrated

Your display will never be more accurate than immediately after calibration by a professional calibrator. THAT is the moment you need to run a profile using your colorimeter – and you must save those results to use as your baseline.

This Profile is bypassing the generic display offsets:

The result of a Profile with any offsets applied
This graph shows our Delta E without any offset applied. In Lightspace I selected Generic CMS to completely bypass the ‘Calibration Settings’ menu.

If I were to read this graph as being accurate, it would force me to fire my professional calibrator! Except I’m measuring with a Colorimeter and a Colorimeter requires offsets to be applied to account for the display technology that’s being profiled.

In this graph, we’ve enabled the OLED generic offset that ships with the i1 Display Pro OEM and re-Profiled the CM250:

The Delta E with Lightspace's generic OLED settings applied
The Delta E with Lightspace’s generic OLED settings applied. Notice how much more ‘in spec’ this display looks… enabling the Calibration Settings and selecting the proper display technology definitely improved the result. But should you trust these raw Delta E values to determine if you need to recalibrate?

MUCH better! The previous two graphs were generated immediately after a full Calibration LUT was created and uploaded to this display. Now, looking at the graph immediately above with a generic OLED offset applied I’d still be pretty tempted to do a full calibration to fix those Delta E values in the brighter part of the grayscale.

Except, I can’t (and shouldn’t) trust the raw results of this graph

As this Insight is designed to demonstrate, there’s too much variability between different makes and models of reference displays and the ‘generic’ profiles and too much variability between the actual colorimeters themselves to trust these raw Delta E values.

But the graph above can be used as my Baseline Profile!

In the months to come, the previous graph shows me how my specific i1 Display Pro reads my FSI CM250 OLED when perfectly calibrated, using the i1 Display Pro OEM’s generic OLED offsets. As this display ages and drifts, I can compare new Profiles to this Profile to determine if it’s time for a re-calibration.

But what if you want more accurate results and graphs from your i1 Display Pro OEM (or any other colorimeter)?

In this Insight, you’ll learn how we can generate Profiles with graphs that are nearly 100% accurate.

What’s really interesting about all this, we can turn our $300 X-Rite i1 Display into a nearly precise measuring instrument!

What we need to do is Characterize our display from a much more accurate Spectrometer. We then compare the results of the Spectrometer to the results of a Characterization from our Colorimeter and generate Offsets that remove the errors from the Colorimeter (we’ll do a later series on how to actually generate your own Custom Matrix in this manner).

Lightspace allows us to load data from a Spectrometer and a Colorimeter, both measuring the same reference display

Lightspace then generates a Custom Matrix. And the Custom Matrix allows us to create graphs that are nearly identical to using a much more expensive, much more accurate and a much slower Spectrometer.

The image below shows our Delta E graph with the exact same i1 Display Pro OEM, but with a Custom Matrix applied at the time of the Profile:

These are Delta E values you can trust, using custom offsets
This graph shows the actual accuracy of this CM250, after a full calibration. But it requires the use of Custom Matrices to get these results. I got the Custom Matrix from Flanders Scientific after sending them my i1 Display Pro OEM for measurement.

This graph tells a MUCH different story than the earlier graphs. This graph tells us there’s almost no room for improvement. This CM250 is well below any threshold that would require a recalibration.

If you use Custom Matrices with your i1 Display Pro OEM you can trust the actual graphs you generate (for a while)

There’s one caveat – over time, all colorimeters drift. About once every 12 months you’re going to need to generate a new set of offsets for your colorimeter – or you won’t be able to trust your graphs any more than you can trust graphs using the Generic Offsets.

How do you get these Custom Matrices for your i1 Display OEM?

This is where things get a bit tricky:

  • To my knowledge, Flanders Scientific is the only display manufacturer that allows their customers to send in their Colorimeters and Spectrometers—and will email you custom offsets, for free (you pay the cost of round-trip shipping). But obviously, they only do this for their own brand of displays.
  • Most of the major markets have a high-end calibrator who owns a Spectrometer – you can have that person come in, calibrate your display and use their Spectro to create the offsets for your Colorimeter (which will probably incur an additional fee).
  • Rent a Spectrometer and create a Custom Matrix yourself.

However you get your custom matrix created – if you can figure out how to get that matrix, whether you use Lightspace or CalMAN, it is definitely worth the extra hassle (and peace of mind) and greatly enhances the value of your investment in the i1 Display Pro!

Coming Up Next: Intro to CalMAN ColorMatch

In the next Insight in this Display Profiling 101 series, we are switching gears to the other major player in the display calibration space, the free CalMAN ColorMatch. It’s a VERY different piece of software – but in the end, it’ll get you to the same place—figuring out if you need to recalibrate your reference display.

-pi

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Comments

Homepage Forums Custom Offsets with the i1 Display Pro OEM in Lightspace DPS

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  • So you can’t use a colorimeter on 2 displays without a spectrometer to generate an offset? Seems very annoying. If i have a I1 can I buy the spectra cal optimized I1 Pro spectrometer to generate per display offsets? I know you said they I1 pro isn’t optimal for led screens or something due the the 10mn sensor. Can you just bypass the colorimeter and use the spectrometer at that point?


  • Patrick Inhofer
    Guest

    The C6 doesn’t solve the problem of colorimeters needing to be profiled and offsets (or matrices) generated… IF you want Delta-E values you can trust. You can buy a spectro, but they’re much slower and much more expensive. I’ve been told that 10nm just doesn’t have the granularity you want if you’re going down this road for the kind of work we are all doing.

    It’s better to figure out how to get offsets created (using a 5nm spectro) or just accept that for $300, you need to establish a baseline Profile against which you’ll measure monitor drift. The move from Profiling to Calibrating is a big leap – Profiling is much less expensive to get into… but there are limitations. Getting around those limitations takes some extra effort.


  • Patrick Inhofer
    Guest

    BTW – Spectral doesn’t seem to sell a branded version of the i1Pro spectrometer. The C6 (both versions) are the i1 Display Pro colorimeter.

  • I meant should I buy this to create offsets for my I1

    http://calman.spectracal.com/store/p24/X-Rite_i1Pro_2_%28Enhanced%29_.html

    The advantage of a spectrophotometer over a colorimeter is that calibrations for each display technology are generally not needed. The accuracy of a spectrophotometer is rooted in its spectral resolution. With the i1Pro’s 10nm spectral resolution, large area spectrums such as those from LED based displays can diminish the meter’s accuracy. We offer an LED enhancement for the i1Pro which is a per meter calibration with our reference Konica Minolta CS-2000. This enhancement table increases the accuracy for the i1Pro on all LED based light engines. This enhancement comes standard on all our i1Pros and can be added to an i1Pro 1 or 2 purchased elsewhere through our calibration services.


  • Robbie Carman
    Guest

    It’s worth noting as Gregg points out ‘tuned’ colorimters ones like the C6 do have generic spectral presets that are generated by a reference grade spectro.

    The same is true for high-end colorimeters like a CR-100 you can go to the Colorimetry Research website and download generic presets (and some specific ones) and load them on a CR-100. Or get them from a display manufacturer for your model – FSI I think will provide these for example.

    Using CCFL or Plasma spectral preset that’s better then not using an option that matches the spectral power of the display you’re using. But the problem of course is those presets/genric offsets are not specfic to your model and actual display.

    So, the next best would be using offsets for the model of display your using – LG B6 OLED for example

    The best workflow is to work offsets created with a spectro on your actual display – LG B6 OLED – Robbie’s Copy

    The issue in my opinion has less to do with offsets/spectral presets but the stability of the colorimeter and it’s filters. Using any type of offsets/presets doesn’t matter all the much if the repeatbility of the colorimeter sucks.

    But to pat’s point the meter one-two punch (spectro/colorimter) is the preferred way of doing it. It lets you create offsets for YOUR display with the spectro and load those on your colorimeter which is way faster of course

    Owning a reference grade spectro is out question for a lot people, so if you can the thing to do is rent one for a day or two create offsets for your colorimeter for all the displays you use

    Our you could be like me and create a new offset prior to every calibration with the spectro (overkill)!

    It think later in this series Pat or I will be showing how to creative offsets with a spectro and loading those on your colorimter.


  • Patrick Inhofer
    Guest

    Robbie and I have been chatting offline about this (and I’ve deleted my previous answer to you as a result of those conversations)…

    So yes, the i1 Pro is a spectro and can be paired with a colorimeter to create offsets. Note that even spectros drift, so you’ll need to get it re-certified on a semi-regular basis. But that’s the way to go if you want to create offsets that are specific to your physical display. And if you’re using an LED-based panel, it sounds like you’ll get good results from the Spectracal i1 Pro.

    RE: 10nm – it’s just a function of accuracy… a 5nm spectro will see spikes in the spectral output of your display that a 10nm spectro won’t, and will be able to compensate for them.

    Note: We’re also reaching out to Spectracal to learn more about this fine-tuning to the i1Pro that they’re doing.


  • Steve Shaw
    Member

    With an i1 Pro there is no way to substantially improve the spectro’s accuracy as it is limited by the 10nm resolution.

    But, all this is relative – if you have a high-end, relatively expensive display, with good internal electronics, it is worth getting an equally high-end probe for profiling.

    If you are using a lower-end display, the limitations of the display’s design will mean you are limited to the level of accuracy you can attain. So chasing ever greater ‘probe’ accuracy becomes irrelevant, to a degree.

    For most ‘basic’ displays, the default pre-sets within i1 Display Pro are ‘ok’. Just remember that aby replacement pre-sets are just the same, just made on different displays with different spectros. The X-Rite pre-sets are made with a true reference Specto, so are just as ‘accurate’ as any other pre-sets.

    We do not use Spectro’s for actual profiling as they are slow, and poor at measuring lo-light levels, unless you spend many 10’s thousands $ on one!

    See: http://www.lightillusion.com/i1_pro_2.html

    This is why FSI provide dedicated pre-sets at a number of levels – a generic one, but for the specific display model you purchase from them; a more dedicated pre-set made on a same model display, but made with YOUR i1D3; a dedicated pre-set made on your actual display with you i1D3.

    (Oh, and the i1 Pro suffers drift due to overheating, so has to be re-set every so often – again making it next to useless for real profiling, where a high number of patches are used.)


  • Steve Shaw
    Member

    Just noticed an issue with LightSpace and the way Patrick uses the ‘Target’ and ‘Actual’ values, and the ‘Zoom and Bars’ widgets to follow what is happening during a Quick Profile!

    We had not intended for that us, as as a result the ‘Actual’ measurement data is one patch BEHIND the ‘Target’ data – the target is always the actual patch being displayed, while the measured data it the patch just measured, so the previous patch!

    To see the correct data go to the ‘Manage Colour Spaces’ library when the profile is finished, and use ‘Display’ to show the graphs again, and click on any point in the graph. You will get a pop-up window with all the data.


  • Steve Shaw
    Member

    Here’s a thought I’ve just had while watching Patrick’s ‘Base Line’ approach to relative calibration/drift comparisons…

    You could actually manually make you own ‘Probe Offsets’ so that when you use the i1D3 you get results that always reference back (absolutely, not just relatively), to the display just after it was ‘calibrated’.

    This takes a bit of thought, but is another example of the ‘flexibility’ within LightSpace.

    Basically, as you know your display is ‘accurate’ as it was calibrated with exceptionally expensive kit just yesterday by a professional calibrator (or the factory), you just need to enter the ‘perfect’ xy coordinates for your target colour space for RGBW as your ‘Reference’ Probe data within the Probe Matching option, and tha actual ‘measured’ values for you i1D3…

    This means LightSpace will generate a pre-set matrix that will show your display as being ‘accurate’ when profiled with your i1d3, just after the display have been professionally calibrated.

    The LUM value within the ‘Probe Matching’ is a tad more tricky, as that uses a 240,240,240 (94%) white patch.

    But, as you know what peak luma the display will have been calibrated to (say 100 or 120 nits?) you can enter 94% of that value.

    You will then have an i1D3 that ‘appears’ to have been ‘matched’ to the high-end spectro that was used to calibrate you display.


  • Patrick Inhofer
    Guest

    Okay. That’s a cool idea! In the wrap up Insight I’m going to share this approach. Brilliant. 🙂


  • Patrick Inhofer
    Guest

    Right. I think I made this point in a previous Lightspace Insight. But a good reminder. Thanks Steve.


  • Patrick Inhofer
    Guest

    Steve – regarding overheating… I know there’s a recommended practice of plugging in a colorimeter for a half-hour to let it warm up. How long before the i1 Display Pro starts to overheat to the point that it effects the readings, assuming comfortable, stable temps and humidity?


  • Steve Shaw
    Member

    It actually depends on the display… for example, plasmas chuck out a lot more heat than an LCD…
    So it is really variable.
    But, when performing a real ‘Characterisation’ for LUT generation (not a Quick Profile for display verification) the time taken on nay display will likely cause overheating issues with the i1 Pro Spectro.


  • Patrick Inhofer
    Guest

    Ah – I mixed up the Spectro and the Colorimeter in my comment above. Right – the Spectracal folks agree, a full characterization using the i1 Pro spectrometer is not recommended (even if you had the time) due to overheating. Which is another reason, I guess, to use the spectro just to get your offsets and use the colorimeter for the full characterization. And… the i1Display colorimeter isn’t subject to the same overheating concern.


  • Balaji Gopal
    Member

    Hey Guys is there any way If I use i1D3 Display Probe with Ezio 4k Display and achieve same results for DCI P3? Can you have some insights I need to get into before profiling and calibration my Ezio 4K Display using Lightspace.

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