And the levels should be applied to the actual layers, not on masks. Unless
I'm misunderstanding you.

2012/3/8 Simon Björk <[email protected]>

> After, as it will make the layers blend in linear light instead of sRGB.
> The overall gamma will be the same as the sRGB viewer lut you have in
> Nuke. Although, you might introduce problems with banding as your really
> bending the colors of 8-bit. Of course you will also clamp values above 1.
> It might be better to do your compositing in sRGB space in Nuke as other
> suggested, but it's worth a try. Essentially, this would be somewhat the
> same thing as using a linear ICC profile in PS.
>
>
> 2012/3/8 Richard Bobo <[email protected]>
>
>> Simon,
>>
>> Are you saying that the .4545 levels effect on the layer masks and the
>> overall 2.2 gamma adjustment should be done before the 32 to 8 bit depth
>> conversion or after...?
>>
>> Thanks,
>>
>> Rich
>>
>> Rich Bobo
>> Senior VFX Compositor
>> Email:  [email protected]                     
>> Mobile:  248.840.2665
>> Web:  http://richbobo.com
>>
>>
>> On Mar 08, 2012, at 03:46 AM, Simon Björk <[email protected]>
>> wrote:
>>
>> Look here to create a linear ICC profile:
>> http://fnordware.blogspot.com/2008/05/making-linear-icc-profile.html. With
>> that set as your working space, you should be able to get correct blending.
>>
>> If you only have a couple of layers, you could try adding a Levels effect
>> and set gamma to 0.4545 to each layer. On the top of your layers you would
>> then need to set an adjustment layer with a gamma of 2.2.
>>
>> /Simon
>>
>>
>> 2012/3/8 Randy Little <[email protected]>
>>
>>> because you are using blend modes in photoshop that do not support
>>> float math(s)   AND/Or you your working space ICC is not set up right.
>>>
>>> Randy S. Little
>>> http://reel.rslittle.com
>>> http://imdb.com/name/nm2325729/
>>>
>>>
>>>
>>>
>>> On Wed, Mar 7, 2012 at 20:43, Richard Bobo <[email protected]> wrote:
>>> > 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
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>>> >> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users
>>> >
>>> >
>>> >
>>> >
>>> > --
>>> >
>>> > Y ella dijo: "La ilusión mueve el mundo"
>>> >
>>> >
>>> > _______________________________________________
>>> > Nuke-users mailing list
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>>> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users
>>> >
>>> >
>>> >
>>> > _______________________________________________
>>> > Nuke-users mailing list
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>>>
>>
>>
>>
>> --
>> --------------------------------
>> 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
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>> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users
>>
>>
>> _______________________________________________
>> Nuke-users mailing list
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>> 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
>
>
>


-- 
--------------------------------
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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