Aha, problem solved after an afternoon of troubleshooting. The layer in Photoshop was set to 98%! So that was why the flattened exported layer just didn't seem to match quite right.
Cheers, Jordan On Oct 20, 2014 3:11 PM, "Jordan O" <[email protected]> wrote: > Time to bump this old thread again- > I am also having issues getting alpha to match between Photoshop and nuke. > > Specifically, between > a) a single layer exported from Photoshop as a TIF with transparency > B) the Photoshop file in Nuke with a shuffle node to isolate the layer > > The alphas just don't match. They're very close, so an obvious one like > sRGB to linear is not the answer. It's not just gamma, the gain/ramp also > is off. > On Apr 29, 2014 4:25 PM, "Frank Rueter|OHUfx" <[email protected]> wrote: > >> oops, sorry, Randy had already said the same - ignore me :) >> >> On 4/30/14, 11:21 AM, Frank Rueter|OHUfx wrote: >> >> Nuke would be doing the comp in linear light, whereas PS does it sRGB, so >> you are probably looking at a gamma discrepancy of around 2.2. >> >> On 4/30/14, 1:51 AM, Florian Einfalt wrote: >> >> Sorry Deke, that doesn't work either. I have a feeling it is happening on >> the PS side of things. >> When I bring the PNG back into Nuke it looks exactly like the original. >> >> Anyone familiar with Photoshop's alpha treatment? >> >> >> On 29 April 2014 14:42, Deke Kincaid <[email protected]> wrote: >> >>> Maybe you have a straight alpha instead of a premultiplied one. So try >>> just adding a premult node. >>> >>> -deke >>> >>> On Tuesday, April 29, 2014, Florian Einfalt < >>> [email protected]> wrote: >>> >>>> Hi Deke, >>>> thanks for that, did it just now and it doesn't change anything >>>> unfortunately. >>>> When does the sRGB LUT get applied actually? >>>> >>>> Thanks. >>>> Flo >>>> >>>> >>>> On 29 April 2014 14:28, Deke Kincaid <[email protected]> wrote: >>>> >>>> Nuke needs to unpremultiply the alpha before applying the sRGB lut and >>>> the premultiply it again. Did you check the "premultiplied" box in >>>> the read node properties next to the lut selection? >>>> >>>> -deke >>>> >>>> >>>> On Tuesday, April 29, 2014, Florian Einfalt < >>>> [email protected]> wrote: >>>> >>>> I have tried to use: >>>> png 8 and 16 bit >>>> exr 16bit float >>>> tiff 8 and 16bit >>>> >>>> Same behavior with all of them. >>>> >>>> >>>> On 29 April 2014 12:20, Martin Constable <[email protected]> >>>> wrote: >>>> >>>> An obvios suggestion maybe, but have you thought about moving your >>>> workflow to tiffs? Or exrs? >>>> >>>> PNGs do not store info as floating point. They use integers instead. >>>> This might be at the root of yr problem. >>>> >>>> >>>> On 29 Apr, 2014, at 6:56 PM, Florian Einfalt < >>>> [email protected]> wrote: >>>> >>>> > I tried both using 8bit per pixel and 16bit per pixel. No difference >>>> unfortunately. >>>> > >>>> > Flo >>>> > >>>> > >>>> > On 29 April 2014 11:51, Martin Constable <[email protected]> >>>> wrote: >>>> > Are yr pngs in 24 bit? That might help. >>>> > >>>> > >>>> > >>>> > On 29 Apr, 2014, at 6:45 PM, Florian Einfalt < >>>> [email protected]> wrote: >>>> > >>>> > > Hello, >>>> > > >>>> > > I am having this problem with PNGs from Nuke that I need to deliver >>>> in a Photoshop psd-file. This specifically concerns the shadow pass of my >>>> comp but generally there is a discrepancy on everything that is not solidly >>>> opaque. >>>> > > >>>> > > My workflow is as follows: >>>> > > - I write my 8-bit PNG out of Nuke using the sRGB colorspace. >>>> > > - When I open the rendered PNG in Photoshop I assign the sRGB color >>>> profile and over a 'transparent' background the shadow looks to have >>>> similar density to the one in Nuke. >>>> > > - When I comp that layer over a white background though, the shadow >>>> is suddenly more dense than in Nuke. Also, there is a much harsher fall-off >>>> in the shadow. >>>> > > >>>> > > Is this because Photoshop treats alpha information differently from >>>> Nuke? >>>> > > >>>> > > I thought I can maybe counteract this by additional grading in Nuke >>>> but even when I grade the alpha gamma to 0.4545 in Nuke and then write the >>>> PNG I get closer but not exactly to the same result. >>>> > > >>>> > > Does anyone have a suggestion? >>>> > > >>>> > > Thanks. >>>> > > >>>> > > Florian >>>> > > >>>> > > -- >>>> > > >>>> > > >>>> > > Florian Einfalt Senior Digital Artist >>>> > > T +44 (0)20 7833 3032 M +44 (0)7808669580 >>>> > > [email protected] >>>> > > >>>> > > Saddington Baynes Ltd | Studio 3, 21 Wren Street. London WC1X 0HF. >>>> United Kingdom | Map >>>> > > Disclaimer | Printing? Consider the environment. >>>> > > >>>> > > _______________________________________________ >>>> > > 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 >>>> > >>>> > >>>> > >>>> > -- >>>> > >>>> > >>>> > Florian Einfalt Senior Digital Artist >>>> > T +44 (0)20 7833 3032 M +44 (0)7808669580 >>>> > [email protected] >>>> > >>>> > Saddington Baynes Ltd | Studio 3, 21 Wren Street. London WC1X 0HF. >>>> United Kingdom | Map >>>> > Disclaimer | Pr >>>> >>>> >>> >>> -- >>> -- >>> Deke Kincaid >>> Creative Specialist >>> The Foundry >>> Skype: dekekincaid >>> Tel: (310) 399 4555 <%28310%29%20399%204555> - Mobile: (310) 883 4313 >>> Web: www.thefoundry.co.uk >>> Email: [email protected] >>> >>> >>> _______________________________________________ >>> Nuke-users mailing list >>> [email protected], http://forums.thefoundry.co.uk/ >>> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >>> >> >> >> >> -- >> >> >> Florian Einfalt Senior Digital Artist >> T +44 (0)20 7833 3032 M +44 (0)7808669580 >> [email protected] >> [image: Saddington & Baynes] <http://www.saddingtonbaynes.com/> >> Saddington Baynes Ltd | Studio 3, 21 Wren Street. London WC1X 0HF. >> United Kingdom | Map <http://signature.saddingtonbaynes.com/map.php> >> Disclaimer <http://signature.saddingtonbaynes.com/disclaimer.php> | >> Printing? Consider the environment. >> [image: Twitter] <http://www.twitter.com/saddbaynes> [image: Facebook] >> <http://www.facebook.com/SaddingtonBaynes> [image: linkedin] >> <http://www.linkedin.com/company/saddington-baynes> [image: pinterest] >> <http://pinterest.com/saddbaynes/> [image: vimeo] >> <http://vimeo.com/saddingtonbaynes> [image: behance] >> <http://www.behance.net/saddington_baynes> [image: instagram] >> <http://instagram.com/saddingtonbaynes> >> >> >> _______________________________________________ >> Nuke-users mailing [email protected], >> http://forums.thefoundry.co.uk/http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> >> >> -- >> [image: ohufxLogo 50x50] <http://www.ohufx.com> *vfx compositing >> <http://ohufx.com/index.php/vfx-compositing> | workflow customisation and >> consulting <http://ohufx.com/index.php/vfx-customising> * >> >> >> _______________________________________________ >> Nuke-users mailing [email protected], >> http://forums.thefoundry.co.uk/http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> >> >> -- >> [image: ohufxLogo 50x50] <http://www.ohufx.com> *vfx compositing >> <http://ohufx.com/index.php/vfx-compositing> | workflow customisation and >> consulting <http://ohufx.com/index.php/vfx-customising> * >> >> _______________________________________________ >> 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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