• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

On Calibrating Pictures in A/V System

rajapruk

Senior Member
Patreon Donor
Joined
Sep 22, 2018
Messages
320
Likes
290
Location
Gothenburg, Sweden
#21
I use the DVE blu-ray to try to set some basic parameters more right.
Gray-scale I use my eyes for.
I have a Infocus IN83 projector, that is not possible to set colors right I think. But now I have an old Samsung A800b on its way. Those are supposed to be possible to get very correct.
10 year old SOTA 1080p dlp projectors are dirt cheap now, and I have a thing for them :)
I paid like $100 for a working Samsung a800b, that is crazy value.
 
Joined
Nov 14, 2018
Messages
8
Likes
9
#22
Well, whatever floats your boat. I did try to make my LG 50PK350 plasma perfect, but it was impossible so I settled to an approximately good and I'm satisfied with it.
But the problem with our eyes is similar to our ears, both are connected to our brain (https://www.datacolor.com/business-solutions/blog-business-solutions/why-cant-we-agree/).
One should be able to find a second hand i1Pro for cheap on ebay, as these devices are usually bundled with color copiers and your local printshop might have several unused ones.
 

andymok

Active Member
Joined
Sep 14, 2018
Messages
118
Likes
35
#23
A bit late to the party, but I hope not too late. I work as a color management technician, specifically in printing - more specifically in offset lithography, so I wouldn't call myself an expert, but I've done a fair amount of measurements and fiddling with knobs and buttons.
Calibrating computer displays is totally different from calibrating TV sets. Modern operating systems use icc profiles for correcting displayed colors. Icc profiles can be generated by characterizing the display (measuring the responses of a set of known RGB input values with a colorimeter and/or spectroradiometer). To get a good icc profile a preliminary calibration is highly recommended - this will linearize the RGB gamma curves (or set the desired gamma curve depending on your use case), set the correct white and black points, etc. It is important to note that any change in display settings (brightness, contrast, backlight level) or changes which develop with aging will require a new calibration and characterization.
For the best results, I use both an X-rite i1Pro (rev E.) spectro and an i1 DisplayPro colorimeter and the excellent and free DisplayCal tool (based on Argyllcms). You'll find much more information and you can become an expert if you read through these sites.
For quick calibration I just use the i1Pro and i1Profiler (not free) and a small testchart - it's usually good enough for me as I don't do retouching.
For professional work, we recommend Eizo CG/CX monitors with built-in hardware calibration and a colorimeter. You just press a button and after 2 minutes you have a calibrated monitor.
For TV calibration there is also a free tool called HCFR (also based on Argyllcms). Since you can't load an icc profile to TV, you have to dial-in the correct values of your preferred standard (sRGB, Rec. BT709, DCI-P3, etc.) starting with White Point and then the correct R,G,B,C,M and Y coordinates followed by Gray balance and Gamma (again as defined in the standard). Depending on your display type and technology the methods and nuances will be wildly different but one can always ask for help either on Argyllcms or AVS forums.
Hey good to have you here!

I learn that the way to achieve best and accurate calibration (or even CM workflow) results would be incorporating 3D LUT conversion to do all the work. I wonder what would be your view on this? More details here: https://www.lightillusion.com/icc_profiles.html
 
Joined
Nov 14, 2018
Messages
8
Likes
9
#24
Hey good to have you here!

I learn that the way to achieve best and accurate calibration (or even CM workflow) results would be incorporating 3D LUT conversion to do all the work. I wonder what would be your view on this? More details here: https://www.lightillusion.com/icc_profiles.html
That is exactly what happens in a monitor with built-in hardware calibration (with or without a built-in sensor), like in Eizo CG series ( or NEC spectraviews, etc.). They have a built-in 3d lut conversion with 10-12-14bits of resolution. There are external Lut boxes, but they are expensive and I don't have any experience with them.

Edit: For the film and Tv industry there are other series of displays eg. : https://www.eizoglobal.com/solutions/graphics/video_editing_and_post_production.html.
That said if you are using a pc for playing back movies , there are players which will honor the the icc profile of your display , like MadVR - and this gives you the flexibility to have different profiles for different viewing conditions and get away with a cheaper solution ( you just need a colorimeter).
 
Last edited:
Joined
Nov 14, 2018
Messages
8
Likes
9
#25
You can have 3d Lut calibration for free with DisplayCal: https://displaycal.net/#create-3dlut
Imho, there is nothing extra in Lighillusions approach, which you can't achieve with other software and a proper setup and with a good enough calibration. You can even produce LUT based profiles with high patch counts instead of matrix ones, and the gamma/vctg is not really based on 1d curve but rather on 1d curve per channel 1 for each primary (R,G,B).
And then in the end, where do you load that Lightillusion 3d LUT?
 

Similar threads

Top Bottom