Re: ICC profile with headroom above SDR was: HTML Canvas - Transforms for HDR and WCG

>
> Do image browsers/editors use canvas?


The Google Photos editor does.

On Mon, May 10, 2021 at 1:41 PM Lars Borg <borg@adobe.com> wrote:

> Here is a simple use case.
> Camera or other source delivers images with this kind of ICC profile.
> Uploaded to Adobe Stock, Lightroom Web, Dropbox or Google or whatever.
> User browses their image library, determines which images are OK vs crap.
> Reasonable fidelity is needed, or else images will look like crap.
> User edits image in image browser/editor.
> Do image browsers/editors use canvas?
>
> Right now, ungraded HDR images come across as too dark in Lightroom Web.
> Seems color management info is missing and it's read as SDR.
>
> Lars
>
> -----Original Message-----
> From: Pierre Lemieux <pal@sandflow.com>
> Date: Sunday, May 9, 2021 at 7:21 PM
> To: Lars Borg <borg@adobe.com>
> Cc: Christopher Cameron <ccameron@google.com>, Chris Lilley <chris@w3.org>,
> "public-colorweb@w3.org" <public-colorweb@w3.org>
> Subject: Re: ICC profile with headroom above SDR was: HTML Canvas -
> Transforms for HDR and WCG
>
> Hi Lars,
>
> I am trying to understand if/how the existence of these images/ICC
> profile combinations affect the Canvas API. It does not look like it
> does, but maybe?
>
> I have added the topic to the agenda of our call on 2021-05-10.
>
> Best,
>
> -- Pierre
>
>
> On Sat, May 8, 2021 at 6:49 PM Lars Borg <borg@adobe.com> wrote:
> >
> > If you have specific questions, that would help.
> >
> > -----Original Message-----
> > From: Lars Borg <borg@adobe.com>
> > Date: Saturday, May 8, 2021 at 3:49 PM
> > To: Pierre Lemieux <pal@sandflow.com>
> > Cc: Christopher Cameron <ccameron@google.com>, Chris Lilley <
> chris@w3.org>, "public-colorweb@w3.org" <public-colorweb@w3.org>
> > Subject: Re: ICC profile with headroom above SDR was: HTML Canvas -
> Transforms for HDR and WCG
> >
> > You're asking for use cases.
> > That will take more time to determine.
> >
> > -----Original Message-----
> > From: Pierre Lemieux <pal@sandflow.com>
> > Date: Friday, May 7, 2021 at 12:40 PM
> > To: Lars Borg <borg@adobe.com>
> > Cc: Christopher Cameron <ccameron@google.com>, Chris Lilley <
> chris@w3.org>, "public-colorweb@w3.org" <public-colorweb@w3.org>
> > Subject: ICC profile with headroom above SDR was: HTML Canvas -
> Transforms for HDR and WCG
> >
> > Hi Lars,
> >
> > It is still not clear to me how these profiles are used and how the
> > images are created.
> >
> > Couple of questions come to mind:
> >
> > - are the images created on an SDR or HDR display?
> >
> > - is the ICC profile applied while the image is created, i.e. is the
> > author manipulating the results of the image after processing through
> > the ICC profile?
> >
> > - in the case of a PNG file, is the image expected to be acceptable on
> > an sRGB display without the ICC profile applied?
> >
> > Best,
> >
> > -- Pierre
> >
> > On Fri, May 7, 2021 at 12:15 AM Lars Borg <borg@adobe.com> wrote:
> > >
> > > In this context any ICC profile with headroom above SDR white is
> applicable.
> > > Adobe currently ships such profiles, all having a significant
> headroom. Also attached.
> > > This covers both cine camera profiles and HDR profiles. All are V4
> profiles.
> > > AFAIK, there are more such profiles in the market place.
> > > (Adobe started shipping such profiles in 2006)
> > >
> > > ARRI LogC3 Wide Color Gamut - El 160
> > > ARRI LogC3 Wide Color Gamut - El 1600
> > > ARRI LogC3 Wide Color Gamut - El 800
> > > Canon Cinema CLog2
> > > Canon Cinema CLog3
> > > e-sRGB
> > > P3 D65 PQ W203
> > > P3 D65 PQ W300
> > > P3 PQ Display Full
> > > Panasonic V-Gamut V-Log
> > > Rec.2100 HLG Scene W63
> > > Rec.2100 HLG Scene W75
> > > Rec.2100 HLG Scene W81
> > > Rec.2100 HLG W100
> > > Rec.2100 HLG W203
> > > Rec.2100 HLG W300
> > > Rec.2100 PQ W100
> > > Rec.2100 PQ W203
> > > Rec.2100 PQ W300
> > > Rec.lTU-R BT.2100 HLG Scene Full
> > > Rec.lTU-R BT.2100 HLG Scene Narrow
> > > Rec.lTU-R BT.2100 PQ Display Full
> > > Sony S-Gamut3.Cine/S-Log3
> > > Sony S-Gamut3/S-Log3
> > > Universal Camera Film Printing Density
> > >
> > >
> > > A user can embed any of the above profiles in these file formats with
> these extensions (using Photoshop).
> > > Other tools can support other formats.
> > >
> > > psd     Photoshop
> > > psb     Large Document Format
> > > eps     Photoshop EPS
> > > jpg     JPEG
> > > jpf     JPEG 2000
> > > jps     JPEG Stereo
> > > mpo     Multi-Picture Format
> > > pdf     Photoshop PDF
> > > png     PNG
> > > tif     TIFF
> > >
> > > Not tested if these work with SVG.
> > >
> > > ICC profiles provide a color transform from RGB to XYZ D50.
> > > ICC profiles do not provide colorimetry info in the style of an ISO
> 22028 color image encoding specification.
> > > These profiles do not do tone mapping, but preserve the headroom.
> > > The relative colorimetric intent, present in all of these profiles,
> together with the chad tag, provides colorimetric values for each RGB value.
> > > A few of the profiles indicate scene-referred colorimetry.
> > > A few of the profiles indicate nits for graphics white.
> > > A few of the profiles contain the draft CICP tag.
> > >
> > > The ICC profile is embedded in the wrapper, not in the codec data
> (AFAIK).
> > > Besides the ICC profile, there is no colorimetry info in the files.
> > >
> > > Lars
> > >
> > > -----Original Message-----
> > > From: Pierre Lemieux <pal@sandflow.com>
> > > Date: Monday, May 3, 2021 at 5:07 AM
> > > To: Lars Borg <borg@adobe.com>
> > > Cc: Christopher Cameron <ccameron@google.com>, Chris Lilley <
> chris@w3.org>, "public-colorweb@w3.org" <public-colorweb@w3.org>
> > > Subject: Re: HTML Canvas - Transforms for HDR and WCG
> > >
> > > Hi Lars,
> > >
> > > I think the group will need details before the group can take any
> > > meaningful action:
> > >
> > > - file format(s) used
> > > - codec(s) used
> > > - colorimetry metadata within the codec (if any)
> > > - colorimetry metadata within the file (if any)
> > > - colorimetry metadata within the ICC profile
> > > - etc.
> > >
> > > Best,
> > >
> > > -- Pierre
> > >
> > > On Mon, May 3, 2021 at 12:13 AM Lars Borg <borg@adobe.com> wrote:
> > > >
> > > > The images with hlg and pq encoding and icc profiles already exist.
> Started several years ago afaik. If you need to know I can find out when we
> shipped our first such profile.
> > > > Doing an hdr canvas with these images would be new.
> > > >
> > > > Thanks,
> > > >
> > > > Lars Borg
> > > > Adobe
> > > > Hawaii
> > > >
> > > > ________________________________
> > > > From: Pierre-Anthony Lemieux <pal@sandflow.com>
> > > > Sent: Sunday, May 2, 2021 2:29:04 PM
> > > > To: Lars Borg <borg@adobe.com>
> > > > Cc: Christopher Cameron <ccameron@google.com>; Chris Lilley <
> chris@w3.org>; public-colorweb@w3.org <public-colorweb@w3.org>
> > > > Subject: Re: HTML Canvas - Transforms for HDR and WCG
> > > >
> > > > > Legacy.
> > > >
> > > > I do not see legacy playing a role here since HDR is new to the web..
> > > >
> > > > On Sun, May 2, 2021 at 5:03 PM Lars Borg <borg@adobe.com> wrote:
> > > > >
> > > > > Legacy.
> > > > >
> > > > > Lars
> > > > >
> > > > > -----Original Message-----
> > > > > From: Pierre Lemieux <pal@sandflow.com>
> > > > > Date: Saturday, May 1, 2021 at 2:26 PM
> > > > > To: Christopher Cameron <ccameron@google.com>
> > > > > Cc: Chris Lilley <chris@w3.org>, "public-colorweb@w3.org" <
> public-colorweb@w3.org>
> > > > > Subject: Re: HTML Canvas - Transforms for HDR and WCG
> > > > > Resent-From: <public-colorweb@w3.org>
> > > > > Resent-Date: Saturday, May 1, 2021 at 2:26 PM
> > > > >
> > > > > > To the original question of "what to do about ICC profiles
> specifying HLG anonymously?".
> > > > >
> > > > > What is the use case for not specifying the pixel color scheme?
> > > > >
> > > > > Best,
> > > > >
> > > > > -- Pierre
> > > > >
> > > > > On Sat, May 1, 2021 at 5:19 PM Christopher Cameron <
> ccameron@google.com> wrote:
> > > > > >
> > > > > > On Thu, Apr 29, 2021 at 10:34 AM Chris Lilley <chris@w3.org>
> wrote:
> > > > > >>
> > > > > >>
> > > > > >> On 2021-04-28 15:23, Christopher Cameron wrote:
> > > > > >> > In all browsers today, for "Colorbars in HLG 203
> display.png", any
> > > > > >> > signal value above 0.75 is clamped to SDR-white.
> > > > > >>
> > > > > >> The choice of 0.75 follows from the HLG specification - a code
> value of
> > > > > >> 0.75 is media white, while a code value of 1.0 is peak white
> and is 12x
> > > > > >> higher luminance.
> > > > > >>
> > > > > >> The choice of clamping all HDR highlights, with no tone mapping
> is an
> > > > > >> easy but bad one. However, dislaying HDR content on SDR is in
> general
> > > > > >> hard; HLG is easier here than PQ (by design).
> > > > > >
> > > > > >
> > > > > > Suppose we have a video that identifies itself as HLG (not
> anonymously), and is displayed using a <video> tag on an SDR device.
> Should it clamp values above 0.75? My answer is "no".
> > > > > >
> > > > > > We have established that it is inevitable that pixel values over
> 0.75 in an image with the ICC profile "Colorbars in HLG 203 display" will
> be clamped.
> > > > > >
> > > > > > To the original question of "what to do about ICC profiles
> specifying HLG anonymously?". My answer would be "treat them as extended
> SDR, not as HLG, and there is no way for them to truly be the same as HLG".
> > > > > >
> > > > > >
> > > > >
> > >
>