Thanks for your reply. The reason that I wanted to do the conversion with a log2lin node is that I need to round trip Alexa clips in After Effects, and at the moment I'm not aware of a way to do that. Although, if I can get close with a log2lin node in Nuke, I think it would be possible to recalculate those numbers for AEs converter. Can't use those expressions, which is a shame.
2011/9/27 egoman <[email protected]> > ** > Dan Walker: > No answer that I'm aware of [image: Sad] > > > Simon Björk: > You can't really recreate the true Log C curve with the standard Log2Lin > node, but you can use the Colorspace node instead. Set the "in" space to > AlexaV3LogC and leave the "out" space to Linear. Be careful of changing the > color primaries (third column) though, as they do not seem to match the Arri > specs (as I mentioned in my last post). > > You can of course also use an Expression node as well. The expression used > by Nuke is: > *Code:* (x > 0.1496582 ? pow(10.0, (x - 0.385537) / 0.2471896) : x / > 0.9661776 - 0.04378604) * 0.18 - 0.00937677 > but this is the one that JGoldstone above said was the correct one: > *Code:* x > 0.1496582 ? (pow(10.0, (x - 0.385537) / 0.2471896) - > 0.052272) / 5.555556 : (x - 0.092809) / 5.367655 > The difference is hardly noticable. > > If you really need to use a Log2Lin node for some reason, you can still get > a fairly good approximation of Log C by using values like: > black: 95 > white: 582 > gamma: 0.51 > That seems to come fairly close for the image I tested it on. Not sure how > well it handles super whites though. > > _______________________________________________ > Nuke-users mailing list > [email protected], http://forums.thefoundry.co.uk/ > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users > -- -------------------------------- Stiller Studios Lidingö/Sweden Simon Björk Stiller Studios +46 (0)8 555 23 560 Ekholmsnäsvägen 40, S-181 41 Lidingö [email protected] www.stillerstudios.se find us: http://www.eniro.se/query?search_word=stiller+studios&geo_area=liding%F6&what=all
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