Just some more discussion. In the future implementations of Windows, and I expect Apple, if the display is set into an HDR mode, you will probably not have access to the general video card luts because they will not be in the HDR pipeline. At Portrait Displays we have provide general guide lines to display vendors for design of there pipe lines if they want us to include their displays in our CalMAN product. Florian mentioned the unreliability of the DDC channel and that is quite correct. It is also deadly slow. Vendors of external displays are required to supply Portrait with a formal SDK based on our guidelines, that we use for calibration support in our application. For low end products that do not support matrix calibration processes, we do default to the internal Gamma Ramp functions. I want to emphasize that using ICC color management with low end displays works quite well with the video card lut . Graeme Gills frustration with proprietary interfaces is well founded, but display vendors don’t want the support call that comes with outside, third party software that can really brick the display if not properly implemented. Displays that offer DCI-P3 gamut MUST have a matrix in the pipeline or they can’t image sRGB natively (but can work quite will with standard ICC color management). In many cases they do not allow access to the matrix from anything other than a color space selection from the display UI. In some cases, they have calibration “slots” that can be accessed but there really is no standard in this area that I am aware of. The TV world is a completely different environment, particularly with respect to UHDR specifications and use of the PQ transfer functions. TV vendors do not want anyone fussing with the internals and the workflows are completely vendor specific. HDR tests are very difficult tests to run because of the need for signal generation. You can get some oversight at https://displayhdr.org/. Calibration of external displays capable of Dolby or HDR10+ standards require the use of meta data. Regards, Tom Lianza Vice President R&D tlianza@portrait.com cell: 603-540 4318 Portrait Displays 6663 Owens Drive Pleasanton, CA 94588 USA portrait.com This message, including any attachments, contains confidential information intended for a specific individual and purpose, and is protected by law. If you are not the intended recipient, you should delete this message and are hereby notified that any disclosure, copying, or distribution of this message, or the taking of any action based on it, is strictly prohibited From: colorsync-users-request@lists.apple.com Sent: Monday, July 8, 2019 3:00 PM To: colorsync-users@lists.apple.com Subject: colorsync-users Digest, Vol 16, Issue 55 Send colorsync-users mailing list submissions to colorsync-users@lists.apple.com To subscribe or unsubscribe via the World Wide Web, visit https://lists.apple.com/mailman/listinfo/colorsync-users or, via email, send a message with subject or body 'help' to colorsync-users-request@lists.apple.com You can reach the person managing the list at colorsync-users-owner@lists.apple.com When replying, please edit your Subject line so it is more specific than "Re: Contents of colorsync-users digest..." Today's Topics: 1. Printer profiling -- Enhance Matte (graxx@videotron.ca) 2. Re: LCD color calibration (Florian Höch) 3. RE: Printer profiling -- Enhance Matte (Wayne Bretl) 4. Printer profiling -- Enhance Matte (graxx@videotron.ca) 5. Re: LCD color calibration (Graeme Gill) ---------------------------------------------------------------------- Message: 1 Date: Sun, 07 Jul 2019 17:25:04 -0400 From: graxx@videotron.ca To: "''colorsync-users?lists.apple.com' List'" <colorsync-users@lists.apple.com> Subject: Printer profiling -- Enhance Matte Message-ID: <056801d5350a$728a50b0$579ef210$@videotron.ca> Content-Type: text/plain; charset="US-ASCII" Super, duper, exceptionally long video on printer profiling. https://www.youtube.com/watch?v=W92nZK53B_0 Finally got a roll of Epson Enhance Matte paper! This is my measurement: CIE Lab (M1): 95.81 1.51 -6.79. I wanted to document the making of an ICC profile for those who have less familiarity with ICC color management. Best / Roger Breton www.graxx.ca ------------------------------ Message: 2 Date: Mon, 08 Jul 2019 00:28:22 +0200 From: Florian Höch <lists+colorsync-users@hoech.org> To: colorsync-users@lists.apple.com Subject: Re: LCD color calibration Message-ID: <2780fb66-0c5f-2fe1-f85c-3fb69afcab3e@hoech.org> Content-Type: text/plain; charset=utf-8 Am 07.07.2019 um 16:33 schrieb THOMAS A LIANZA via colorsync-users:
Communication is possible to nearly all displays using some level of the DDC 2.0 specifications.
Not always very reliable though, and the DDC specification(s) lack consistent implementations, which seems to prevent general applicability (i.e. to me it looks like calibration software vendors are mostly forced to support DDC capable displays individually and often cannot rely on a common set of capabilities or even instruction sets).
A wide gamut panel will necessarily have an input lookup table, a matrix or 3D out, followed by a display look up table.
While a matrix or 3D LUT is not a requirement, it's surely nice-to-have for supporting things like an sRGB mode, and/or "advanced" calibration, inside the display itself.
In general, use of the graphic card LUT is not recommended at all in most modern calibration environments.
Well, we'd need to define "most". My definition of "most" with regards to (computer) display calibration would encompass typical desktop systems which either run a version of Windows (very common), macOS (less common) or an open source desktop (e.g. GNOME/KDE, even less common) paired with a run-of-the-mill LCD monitor. Unless Microsoft (same as Apple) decides to no longer support setting graphics card 1D LUTs ("videoLUT") via OS APIs, I don't see this functionality going away anytime soon, and it is still the main functionality that most calibration packages are relying upon (due to widespread support across different platforms).
If a display has an HDMI interface, the graphic card LUT is normally inaccessible because there are a number of assumptions about the display color management.
Hmm. My own experience thus far has been that the actual physical connection or even interface seems to be irrelevant regarding whether or not typical videoLUT functionality will be available. The only requirement really is that support for the respective generalized OS APIs is implemented at the graphics driver level (and there are some USB3 external "graphics cards" which indeed seem to not implement it). Whether that means actual hardware LUTs, or emulated in software, is up to the implementation.
The current processes generally calibrate the displays to a given color space and use a very simple ICC profile to describe the display setup.
This assumes rather high-end display hardware though, that not everyone owning a calibration device will have access to (certainly more common in professional or semi-professional environments).
As the industry moves towards HDR (high dynamic range) and Wide Gamut, calibration occurs in the display, not on the driving platform.
It may be a bit too early to anticipate, but FreeSync2 HDR which is (imho) quite likely to see some adoption (with even major LCD TV vendors onboard) seems to move in the opposite direction, with most or all HDR processing delegated to the graphics hardware in the connected system(s).
The ICC profile is used as a container for other information in HDR systems in Windows 10.
AFAIK, videoLUT still applies in HDR mode, although personally I currently have no ability to check, lacking a HDR-capable display. Cheers, Florian Höch ------------------------------ Message: 3 Date: Sun, 07 Jul 2019 19:12:55 -0700 From: Wayne Bretl <waynebretl@cox.net> To: graxx@videotron.ca, "''colorsync-users?lists.apple.com' List'" <colorsync-users@lists.apple.com> Subject: RE: Printer profiling -- Enhance Matte Message-ID: <00b701d53532$aa09e5f0$fe1db1d0$@cox.net> Content-Type: text/plain; charset=UTF-8 YouTube says the video has been removed by the user. -----Original Message----- From: colorsync-users <colorsync-users-bounces+waynebretl=cox.net@lists.apple.com> On Behalf Of Roger Breton via colorsync-users Sent: Sunday, July 07, 2019 2:25 PM To: ''colorsync-users?lists.apple.com' List' <colorsync-users@lists.apple.com> Subject: Printer profiling -- Enhance Matte Super, duper, exceptionally long video on printer profiling. https://www.youtube.com/watch?v=W92nZK53B_0 Finally got a roll of Epson Enhance Matte paper! This is my measurement: CIE Lab (M1): 95.81 1.51 -6.79. I wanted to document the making of an ICC profile for those who have less familiarity with ICC color management. Best / Roger Breton www.graxx.ca _______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/waynebretl%40cox.net This email sent to waynebretl@cox.net ------------------------------ Message: 4 Date: Sun, 07 Jul 2019 22:50:06 -0400 From: graxx@videotron.ca To: "''colorsync-users?lists.apple.com' List'" <colorsync-users@lists.apple.com> Subject: Printer profiling -- Enhance Matte Message-ID: <05b601d53537$da43fda0$8ecbf8e0$@videotron.ca> Content-Type: text/plain; charset="US-ASCII" This is the update link. https://www.youtube.com/watch?v=aZVZ-VHTe_4 The sound was terrible. Best / Roger Breton www.graxx.ca ------------------------------ Message: 5 Date: Mon, 08 Jul 2019 13:58:24 +1000 From: Graeme Gill <graeme2@argyllcms.com> To: ColorSync List <colorsync-users@lists.apple.com> Subject: Re: LCD color calibration Message-ID: <ce20f95f-2e5b-e7d8-4749-e066b328af63@argyllcms.com> Content-Type: text/plain; charset=windows-1252 THOMAS A LIANZA via colorsync-users wrote:
A wide gamut panel will necessarily have an input lookup table, a matrix or 3D out, followed by a display look up table. In general, use of the graphic card LUT is not recommended at all inmost modern calibration environments.
Nice in theory, useless in reality, because there are no standards. There is no standard, reliable API for discovering and manipulating a displays internal capabilities - the display makers all play the proprietary game, and the OS makers don't have good, reliable API's for accessing these capabilities. In contrast, there are standard, reliable API's for accessing video card per channel lookup tables. Given that the ICC profile format has been sabotaged in regard to display profile absolute colorimetric intent, the video card calibration curves are the only standard mechanism available for software to set white point and brightness. If this is ever to be improved, an effort at standardization amongst display makers and OS vendors is needed, that will overcome the tendency of vendors to be secretive and play proprietary games. Graeme Gill. ------------------------------ Subject: Digest Footer _______________________________________________ colorsync-users mailing list colorsync-users@lists.apple.com https://lists.apple.com/mailman/listinfo/colorsync-users ------------------------------ End of colorsync-users Digest, Vol 16, Issue 55 ***********************************************