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15 Apr 2011

i1 Profiler - Displays & Projectors






In this last blog looking at the new i1 Profiler software I’ll be covering monitor and projector profiling. The only instrument that is supported for display profiling is the i1 Pro, which is a shame since the i1 Pro spectrophotometer doesn’t measure low light values as well as a colorimeter, such as the i1 Display 2, although the i1 Pro can be more accurate at higher brightness values.

The Display Profiling workflow is pretty intuitive, even if you’ve never used a monitor profiling system before. The first option you get is to choose the White Point of your monitor, D65 (6500K) is the default. You can choose from a range of common values or measure your ambient lighting. The Luminance value defaults to 120 cd/m2. You also get to choose the Contrast Ratio, which is usually a factor of the luminance of the white point divided by the luminance level of the black point. If you are profiling multiple monitors then having the same contrast ratio can help to get a visual match. You’d have to profile each screen, see what contrast ratio each has and then set them all to the lowest value. The trouble with this approach is that most of the screens are no longer displaying at their full potential and are being dumbed down slightly.

The Profile Settings page allows you to set options such as Tonal Response Curve, Chromatic Adaptation and ICC Profile Version. Most customers won’t need to change from the defaults, apart from those using older versions of Photoshop who may find a version 2 ICC profile works better for them.

Once you click on the Measurement page you’ll see options to use Automatic Display Control (ADC) or Adjust brightness and contrast manually. Many monitors support ADC for automatic adjustment of the monitor. Both my MacBook Pro screen and my Lacie 324 have this feature, for example. Other monitors may not be able to be adjusted automatically and so you’ll have to interactively measure and adjust the brightness.

Interestingly you don’t get the option of adjusting the white point at all. i1 Profiler adjusts the video look up table of your graphics card to get the correct white point. This can be a good approach for cheaper monitors with poor controls but many monitors do have good adjustments for colour and it is disappointing not to be given the option of interactively changing and measuring the white point of the monitor. However, it did adjust the white point of my monitor using ADC but not precisely enough that it didn’t still have to make adjustments in the graphics card.

After the measurements have been done you can go on to the ICC Profile page and Create and save profile. You can then look at a graph of the gamut of your monitor and a graph of the adjustments made in the graphics card. You also get to see the range of Roman test images you get in the CMYK Printer Profiling workflow, and also have the option of loading your own. When you are viewing the test image you can click a before or after button to see the change in your monitor.

To further test your new monitor profile you can access the Display QA workflow. This takes the reference values from the classic 24 patch ColorChecker card, displays them on screen and then measures how close your monitor comes to displaying the colours accurately. Most previous monitor validation software I’ve used simply puts a series of colours through a profile, and then measures them to check the internal consistency and accuracy of the profile. The i1 Profiler approach of how well the monitor can display certain reference colours is different and I can see the benefit of it. What I would say though is that the little message you get at the bottom of the QA Report page, that the reference uses different measurements and some of the differences might be due to that, is not that reassuring. I’m assuming the reference values were done in D50 and since I profiled my screen at D65 that might be the difference X-Rite are referring to but a little more explanation or factoring in of the differences might make this feature more useful. I first profiled my display to 120 cd/m2 as usual and it failed the QA test but when I put it up to 140 cd/m2 it passed, just.


Now, I’ll be the first to admit that since I got the BasicColor Discus I have been slightly spoilt when it comes to monitor profiling. The profiles the Discus makes the best monitor profiles I’ve ever seen. That said i1 Profiler with an i1 Pro does a competent job that compares favourably with those from a ColorMunki, Spyder3 Elite or i1 Display 2. However, since i1 Profiler is X-Rite’s top of the range profiling product they could have put a few more features in to the Display Profiling workflow to reflect this. I think the lack of white point adjustment is a major omission and I also think an extended Display QA workflow that included uniformity checking would be good.

The Projector Profiling workflow is basically similar to the Display Profiling workflow, but you get no option to adjust the projector, the software simply profiles it as it is. You’ll need the Beamer attachment for your i1 Pro to profile a projector. The Projector QA workflow is also the same as Display QA. The projector profiles I got were slightly better than i1 Match.

My blog has covered all the major aspects of i1 Profiler now, but I’ll revisit it again in a few months after I’ve used the software on-site a bit more for customers. I used it yesterday for customer to profile their digital printing onto cloth and it did a very good job of profiling a difficult process and all the printer profiles I’ve made so far have been very good.

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