> > The source for the pngWriter is supplied with Nuke so you can add the > unpremult option yourself - it’s in the Documentation/NDK/examples folder. > > fwiw that plugin is quite old (circa 2003/2004) and predates the Foundry > by at least 3 years, so the plugin has likely had little production testing > outside of DD’s limited need for it - i.e. web images with no alpha. > > Recommend putting in a feature request to the Foundry to add the unpremult > option. >
Thanks for that, will post a feature request. Mikael > > -jonathan > > On Jul 25, 2014, at 7:32 AM, Mikael Sundell <[email protected]> > wrote: > > Hi! > > Dare I even ask why people are writing PNG files from Nuke? It's not >> exactly a VFX-friendly file format. >> > > In this case we use Nuke to prepare production assets for webreviews and > distribution. > > >> You can force some kind of conversion with oiiotool. If you have a file >> that saves as PNG but that somehow you know is already premultiplied, you >> could try "oiiotool --no-autopremult in.png -o outputfile.ext" to suppress >> the premultiplication that would ordinarily happen when reading PNG files, >> then write to a new file. >> > > Sounds like a plan! > >> But you are right, if you assume that Nuke doesn't know if alpha is >> associated or not, and some nodes assumes it's not and some assume that it >> is, then the situation can't really be improved other than perhaps a option >> on the file writer to make it more obvious. >> >> That's what I had in mind too, just a checkbox in the Nuke PNG > reader/writer to highlight the potential problem. It's not just the oiio > reader that premultiplies, Photoshop and other Adobe products does it too. > They force premultiply based on how data should be present according to the > PNG specification. > > Thanks all! > > Mikael > > _______________________________________________ > Oiio-dev mailing list > [email protected] > http://lists.openimageio.org/listinfo.cgi/oiio-dev-openimageio.org > > > > _______________________________________________ > Oiio-dev mailing list > [email protected] > http://lists.openimageio.org/listinfo.cgi/oiio-dev-openimageio.org > >
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