I just saw that at NAB Sony is releasing an update to there ACES implementation as well as s-log3 for the f65. So Maybe they had something that wasn't quit right with their ACES implementation?
Randy S. Little http://www.rslittle.com/ http://www.imdb.com/name/nm2325729/ On Thu, Mar 6, 2014 at 11:51 AM, Alex Fry <[email protected]> wrote: > The ACES values are scene linear. > > The difference with scene linear files you would have previously been > working with, is that whilst they would have been scene linear in their > intensity, but their primaries are effectively display referred (either > Rec709 primaries or P3). Because their gamut and whitepoint already match > your display device a simple 1D transform will give you a viewable result. > > ACES stores values using the much wider primaries shown below, they are > wide enough that they cover all of the visible colours in the horseshoe of > the spectral locus. > When you look at the Yxy diagram below, you have to remember that big > Y/brightness (the intensity of the pixel) is collapsed into the Z axis, so > you have to imagine it coming out of the screen towards you. > > The scene linear files you would have used in the past can only represent > colour within the green or blue triangles, ACES can represent colours > across the entire spectral locus (plus some imaginary colours outside the > horseshoe but within the ACES triangle). But the total sum brightness, and > its linearity relative to light levels in the scene remain the same. > > I was under the impression that one of the main points of ACES is to use >> the linear light state as the common ground for all colour qworkflows > > > It is. > And part of that is divorcing the primaries from either the input device > or output device. > > [image: Inline image 1] > > > On Thu, Mar 6, 2014 at 10:19 AM, Frank Rueter <[email protected]>wrote: > >> Thanks. >> >> Using OCIO and RRT (sRGB) yields the expected result. I guess my >> confusion was/is with the fact that ACES linear does not produce the result >> I expected from scene referred linear data, and I was under the impression >> that one of the main points of ACES is to use the linear light state as the >> common ground for all colour qworkflows, as it should represent the light >> data captured on set irrelevant of input output signals. >> >> In other words, I would a have expected ACES linear to be a lot closer to >> the linear light images I have been working with over the years. >> >> It may just be a case of un-learning things to be able to understand this >> fully. >> >> Cheers, >> frank >> >> >> On 3/6/14, 8:17 AM, hxpro wrote: >> >>> >>> >>> On 03/03/2014 19:52, Frank Rueter wrote: >>> >>>> Actually, scratch that, ACES linear followed by rec709>linear in Nuke >>>> doesn't look like anything I see in RawViewer in terms of saturation. >>>> The gamma looks reasonable though. >>>> >>>> Any more hints? >>>> >>> >>> ACES uses very saturated primaries (in chromaticity terms), this means >>> that just performing a 1D colour space conversion will result in >>> desaturated looking images. You need to use something like the RRT+ODT to >>> convert to something 'filmic', or at least you need to map from the ACES >>> primaries into the rec709 primaries somehow. You'd need to be careful doing >>> so due to gamut missmatches, which is where a lot of the challenges are. >>> >>> Kevin >>> >>> ---------- >>> This email and any attachments to it are confidential and are intended >>> solely for the use of the individual to whom it is addressed. Any views >>> or >>> opinions expressed are solely those of the author and do not necessarily >>> represent those of Cinesite VFX Ltd. If you are not the intended >>> recipient >>> of this email, you must neither take any action based upon its contents, >>> nor copy or show it to anyone. Please contact the sender if you believe >>> you have received this email in error. >>> Warning: The recipient should check this email and any attachments for >>> the >>> presence of viruses. Cinesite VFX Ltd accepts no liability for any damage >>> caused by any virus transmitted via this email. >>> >>> Cinesite VFX Ltd. Registered Office: Medius House, 2 Sheraton Street, >>> London W1F 8BH. Company registration # 08492749 >>> ---------- >>> _______________________________________________ >>> Nuke-users mailing list >>> [email protected], http://forums.thefoundry.co.uk/ >>> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >>> >> >> _______________________________________________ >> Nuke-users mailing list >> [email protected], http://forums.thefoundry.co.uk/ >> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> > > > _______________________________________________ > Nuke-users mailing list > [email protected], http://forums.thefoundry.co.uk/ > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >
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