Hi Gavin, As you said yourself, the equation cannot be solved UNLESS you know both variables on one of the sides. In other words, you'd need to have the BG image in order to prep a FG image so it can be comped in sRGB space and match the results of a linear comp.
So is there no way to output a PSD or PNG or TIFF which will look the same > as my composite in Nuke over a white background? If you need to get the same results on a white background, you could prep your FG element such that: X = ( (FG * alpha + (1 - alpha)) ^ 2.2 - (1 - alpha) / alpha ) ^ (1/2.2) Where X is the FG image you'd want to export to be comped on a white BG. But of course, this will only give you a match when comping the FG over a WHITE BG. If the BG changes, then you'd need to prep a different FG to go with it. Hope that helps. Cheers, Ivan On Mon, Nov 14, 2011 at 12:13 PM, Gavin Greenwalt <[email protected]>wrote: > How are Nuke users handling workflows in which they need to deliver images > with alpha that will be composited in sRGB space not linear space? > > Essentially we have a situation where you would need to find equations for > u and v such that (xy + z(1-y))^(1-2.2) = (uv + z^(1-2.2)(1-v)). > > My initial impression is that it's impossible since the simplified version > of this conundrum would be (x+y)^2 = (u+v) which I believe is > mathematically impossible to solve... right? So is there no way to output > a PSD or PNG or TIFF which will look the same as my composite in Nuke over > a white background? > > Thanks, > Gavin > > _______________________________________________ > 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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