Adrian, Thanks for wanting to help!
Here are the parameters: -- CG render passes, comped and beautified in Nuke (auto work)... -- Ultimate deliverables for client are layered 8 bit TIFF files with alpha out of Photoshop (different parts of vehicle)… In order to ease the workload, we are trying to render layered files out of Nuke that get loaded into Photoshop. There is some automated work that is done with a recorded macro/droplet in Photoshop and the end result is our client-ready 8 bit layered TIFF .psd file. It would be *perfect* if we could render out an 8 bit layered file of some kind from Nuke. The only reliable layered file format that I know of coming out of Nuke is EXR. And, I don't think Nuke will produce a layered TIFF or DPX that Photoshop can read properly. I could be wrong about that and if I am, I'd love to know how to do it! Also, EXR output does not allow 8 bit, as far as I can tell. So, we've tried 32 and 16 bit EXRs. The OpenEXR Photoshop plugin does a nice job of loading the EXR files, either as premultiplied layers with transparency or as unpremultiplied, separated layers for fill and alpha. The look of the layer comp in Photoshop matches Nuke as long as we stay in 32 bit linear space in Photoshop. However, changing the bit depth to 8 bit results in a general darkening of the image layers and a different "gamma look" to the transparent areas. In other words, the nice linear gradients are squashed in some areas and not as "spread out". The ProEXR manual does speak about this kind of problem and suggests bringing in the layers unpremultiplied and using Levels adjustments on the layer masks only of each layer before changing the bit depth. With some trial and error, I have been able to find some values that will *almost* work. However, the levels adjustment values are not the same for each layer. And, it still does not look quite right. Photoshop *will* produce the correct result, however, *if* we choose to Merge the layers before doing the 32-->8 conversion - but that's not what we need - we need the layers... So, for the moment, we are going to try and see if we can live with individual Levels adjustments for each layer in Photoshop, prior to the bit depth conversion. That may be the path of least resistance - but it sure ain't pretty! (8^P So, Adrian, I hope that explains things a bit better. if you have any suggestions, I would love to hear them! Thanks, Rich Rich Bobo Senior VFX Compositor Mobile: (248) 840-2665 Web: http://richbobo.com/ "Man has been endowed with reason, with the power to create, so that he can add to what he's been given." - Anton Chekhov On Mar 7, 2012, at 6:24 PM, Adrian Baltowski wrote: > Hi > > I want help or advise you something but I don't fully understand your > workflow... > You can of course make color conversion in nuke. Nuke is brilliant software > to make such a conversions BUT.... What next?? You cannot export layered > tiffs out of Nuke (at least not in usable form). Do you want to export layers > as separate tif files? > If you could explain your workflow then we could advise you more. > > > > Best > Adrian > > > W dniu 2012-03-07 16:33:54 użytkownik Juan Galva <[email protected]> > napisał: > keep us posted, please! > > On 7 March 2012 16:27, Richard Bobo <[email protected]> wrote: > Thanks, Julik, Andy, Diogo and Simon for your suggestions, ideas and > questions... > > After trying a number of things and reading some more about the way ProEXR > and Photoshop handle things, we're going to try to make our tweaks in Nuke > and let Photoshop do whatever it does. It may take a few rounds of tweaking > and converting to see just what we need to do on the Nuke side to make it > come out the way we want on the Photoshop end. However, it seems like there > are just too many variables there. So, we'll not try to fight it... (8^ > > Thanks for your help! > > Rich > > Rich Bobo > Senior VFX Compositor > Email: [email protected] > Mobile: 248.840.2665 > Web: http://richbobo.com > > On Mar 07, 2012, at 07:00 AM, Simon Björk <[email protected]> wrote: > > In what application are you comparing the result of the TIFFs? Nuke or > Photoshop? I believe Photoshop use linear light math when in 32bpc and in > that case, the blending of layers (and brightness) will look different if you > change your project to 8 or 16-bit. > > > > 2012/3/7 Julik Tarkhanov <[email protected]> > > On 7 mrt 2012, at 01:51, Rich Bobo wrote: > > The problem is that we need to get 8 bit layered TIFs out of Photoshop. > I think the first problem is that the Photoshop blending is profoundly > affected by the bit depth. > The second problem is that if Nuke does a 1D lookp table conversion from one > kind of RGB to another > (including bit depth upgrades), Photoshop goes via Lab so what is happening > is more like to a 3D LUT. > > What happens in your case is that probably Photoshop is converting the layers > first, and then the result of the blending > modes changes the way the images look. Maybe it's an issue with layer mask > and front unpremultiplication and conversion. > > For me the first thing to check would be the PS profile settings for 8-bit > RGB. Also, where do the discrepancies occur the most? > Blended layer edges? Maybe your workflow needs to be related to manually > unpremulting layers by the layer transparency and > preadjusting the transparency grays... > -- > Julik Tarkhanov | HecticElectric | Keizersgracht 736 1017 EX > Amsterdam | The Netherlands | tel. +31 20 330 8250 > > cel. +31 61 145 06 36 | http://hecticelectric.nl > > > > > _______________________________________________ > 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 > > > _______________________________________________ > 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 > > > > -- > > Y ella dijo: "La ilusión mueve el mundo" > > > _______________________________________________ > 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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