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ICC profile based Calibration

 
 
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Author Steve

INF
Male
#16 | Posted: 18 Jun 2016 08:01 
Using the i1Profiler software is not recommended at all.

You need to follow the instruction in the User Guides within this website.

For example: http://www.lightillusion.com/display_calibration.html
And: http://www.lightillusion.com/lut_calibration_idiots_guide.html

Basically, you need to use the minimum of display pre-sets prior to performing LightSpace CMS calibration.

Steve
Steve Shaw
Mob Boss at Light Illusion

Author GrizzlyAK
ZRO
#17 | Posted: 18 Jun 2016 08:38 
Steve, thanks for the response, but I've already read (and re-read) the links you provided, and user's guide, but it is very specific to your product. None of it answers the questions I posed earlier regarding resetting my monitor to initial settings, except that you say "The key here is to use the minimum number of controls within the display", but as I pointed out, my display doesn't have a master 'reset' switch, so just leaving it as is, in some indeterminate state, I suspect, is not a good starting point under any CMS. I understand you are trying to sell a product, but I'm here as a humble indy filmmaker to learn CM in general so I can finish my short film grading in some form or fashion with a bit of success. Purchasing yet another CMS or more gear is just not in the cards. Unfortunately, I'm going to have to make do with what I have. Perhaps I'm just on the wrong forum.

Cheers,
Shane

Author Steve

INF
Male
#18 | Posted: 18 Jun 2016 08:51 | Edited by: Steve 
Unfortunately we cannot answer specific questions relating to non-Light Illusion products.
While we have tested just about all alternative calibration systems, and therefore know their likely level of accuracy (poor with i1 Profiler) we do not know real specifics.
You may get support form X-Rite?

But, attempting to use i1Profiler for professional calibration is unlikely to get you viable results, especially within a film and TV environment. You will very possibly find different results when the i1 Profile software is used, and then when the creative software is in use... this is an issue common with many ICC based calibration environments.

At least with the free LightSpace DPS and your i1 Pro probe you will be able to verify the accuracy of your display, independently of the i1 Profile software.

Steve
Steve Shaw
Mob Boss at Light Illusion

Author John Barclay
ZRO
#19 | Posted: 8 Jul 2017 17:17 
Jumping on this thread a little but the query is related. Let's assume the editing software in question is not ICC aware. (Fusion, Nuke, most 3D apps etc..).

What is the quality difference between ICC calibration and hardware 3D lut calibration? Aside from the fact that ICC profiles are a real pain when dealing with mixed software cross-platform which does happen in the motion industry! I assume there is some difference between how 3D luts interpolate vs. the VCGT.

What I am considering is to use better ICC profiling for artist monitors for the time being as switching even one department in our studio to hardware calibration isn't going to happen overnight.

Author Steve

INF
Male
#20 | Posted: 8 Jul 2017 18:29 
The Graphics Card VCGT is a 1D LUT only, so has no 'colour calibration capability (gamut), and only controls the greyscale/white point.

Steve
Steve Shaw
Mob Boss at Light Illusion

Author John Barclay
ZRO
#21 | Posted: 8 Jul 2017 18:44 | Edited by: John Barclay 
Steve:
The Graphics Card VCGT is a 1D LUT only, so has no 'colour calibration capability (gamut), and only controls the greyscale/white point.

Hey Steve,

Is it not 1D per channel though? How else when one calibrates with a consumer device/software does it affect the colour, without manual setting of temp etc? My anecdotal evidence aside ICC profiles are used to covert from RGB to CMYK right so some colour translation must be going on?

If the ICC profile specifies just a gamma curve function (per channel) I can see how a 3D lut would still be more accurate.

Or is it literally a 1D gamma function with an additional offset for the white point?

J

Author Steve

INF
Male
#22 | Posted: 8 Jul 2017 18:51 
A mono 1D LUT would just alter gamma, not the grey scale/white point...
(What you probably would refer to as colour temperature)

To alter gamut (saturation) you need a 3D LUT, or as is used with poor calibration a 3x3 matrix.

Most ICC profiles use a 3x3 matrix for gamut control, not a 3D LUT, so is only ever capable of a poor level of calibration.

The ICC profiles you can create using SpaceMan ICC do have a 3D LUT within the ICC, which is a direct copy of the 3D LUT data the ICC is generated from.

See: http://www.lightillusion.com/spaceman_icc.html
And: http://www.lightillusion.com/spaceman_manual.html

To better understand VCGTs see: http://www.lightillusion.com/spacematch_dcm.html

Steve
Steve Shaw
Mob Boss at Light Illusion

Author John Barclay
ZRO
#23 | Posted: 8 Jul 2017 19:02 
Right OK that's good to know.

The GFX card software usually has it's own gamma-per-channel operations so that's why I was assuming that there were 3 1D gamma functions. There was also some noise on the internet with folk invoking per-channel gamma functions.

I'll definitely have a look at SpaceMan ICC also, looks very useful. And again many thanks for your assistance on the topic!

J

Author Steve

INF
Male
#24 | Posted: 8 Jul 2017 21:37 
Yes, a 3 channel 1D LUT will control gamma per colour channel, as that is how it manages to control the grey scale colour temperature.

Steve
Steve Shaw
Mob Boss at Light Illusion

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 ICC profile based Calibration

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