sRGB profile in maya color management

[Gary Jaeger]

I've been working to nail down Maya's color management.

I was struggling to get sRGB swatches to match between linear rendered images in maya to the same swatch dropped into nuke. they were close, but not exact. Then I changed the colorspace of the sRGB swatches in nuke to gamma1.8, and boom now they're exact. Not right, but they match. 

So that leads me to believe that maya is actually interpreting it's sRGB images as gamma 1.8?

Can anybody confirm? and why would they do that? And lastly, anybody know how can I create a color profile for maya that's actually sRGB or gamma 2.2? In fact the manual talks about custom color profiles, but I don't see how to actually modify them.

anybody have experience with this?

. . . . . . . . . . . .

Gary Jaeger // Core Studio

86 Graham Street, Suite 120

San Francisco, CA 94129

415 543 8140

http://corestudio.com

[Gary Jaeger]

Here is an annotated render and comp that might help explain. notice the 8bit textures that are set to sRGB in maya seem to actually being interpreted as gamma 1.8

[Tim Leydecker]

Hey Gary,

any chance you work on a MacOS X version of Maya?

Between OSX 10.5 and 10.6, Apple changed the default
gamma from 1.8 to 2.2, maybe this slipped ADSKs notice?

Cheers

tim

On 23.01.2011 06:13, Gary Jaeger wrote:
> Here is an annotated render and comp that might help explain. notice the 8bit textures that are set to sRGB in maya seem to actually being interpreted as gamma 1.8
>
>
>

[Gary Jaeger]

Yeah that's what I was wondering. But still seems crazy to only have the one sRGB profile without a way to modify it

. . . . . . . . . . . .
Gary Jaeger // Core Studio
86 Graham Street, Suite 120
San Francisco, CA 94129
415 543 8140
http://corestudio.com

[Gary Jaeger]

and besides, doesn't sRGB have a very specific definition? seems like maybe maya is using the term but they are actually doing something different.

[Gary Jaeger]

wow, what a fun adventure this has been. Yes I'm on OS X.

Seems like maya is ALSO changing the color when writing to .exr files. Below is a screen grab with maya render view on the left and a nuke split window on the right. tif works as expected, but exr (which is convenient for us in this case) has some odd color shift, not some simple gamma thing

[Phinnaeus OConnor]

I've just recently started using sRGB colour management system in Maya 2011 with the profile set to linear as maya and MR renders in linear colour space, The sRGB setting to compensate because our monitors work in sRGB. 

If you are rendering, using FG or HDRI out to 8bit tiff, tga etc, then you need to hook up a mia_exposure_simple MR lense shader in to the camera and turn up the gain and knee settings to 1, bring the compression  down to 0 and leave the gamma at the default 2.2. If you use the Physical Sun Sky light rig then it automatically puts in the mia_exposure_simple in for you, just remember to change theses settings.

This should hopefully sort out your colour space problems, don't forget to select the linear option when bringing in textures too

Remember If you are rendering to to 32bit exr etc, then don't forget to take off the lense shader before rendering.

Hope this helps

Phin

---

From: Gary Jaeger <ga...@corestudio.com>
To: maya...@googlegroups.com
Sent: Sun, January 23, 2011 2:45:33 PM
Subject: Re: [maya_he3d] sRGB profile in maya color management

and besides, doesn't sRGB have a very specific definition? seems like maybe maya is using the term but they are actually doing something different.

On Jan 23, 2011, at 6:11 AM, Gary Jaeger wrote:

Yeah that's what I was wondering. But still seems crazy to only have the one sRGB profile without a way to modify it

. . . . . . . . . . . .
Gary Jaeger // Core Studio
86 Graham Street, Suite 120
San Francisco, CA 94129
415 543 8140

http://corestudio.com/

On Jan 23, 2011, at 2:42 AM, Tim Leydecker <baue...@gmx.de> wrote:

Hey Gary,

any chance you work on a MacOS X version of Maya?

Between OSX 10.5 and 10.6, Apple changed the default

gamma from 1.8 to 2.2, maybe this slipped ADSKs notice?

Cheers

[Gary Jaeger]

Thanks Phin. Did you see the image? I do understand the color management and linear workflow, but as far as I can tell I have two problems, at least on the mac side:

1. maya is saying it's using an sRGB profile but it's actually using a gamma 1.8 profile. I can get around this a few ways (convert the sRGB files in nuke or add a gamma .818 in maya)

2. maya is modifying the color somehow when it's writing a 32 bit linear .exr file. The color is correct for 32 bit linear tif files. the only way to solve this is to not use .exr

btw I think using the lens shader and gamma nodes is no longer necessary if you're using maya's new built in color management. that was necessary before maya supported color profiles for file nodes

[Tim Leydecker]

Isn�t it nice how big the can of worms is, once you�ve opened it?

*bug in Maya/MacOS *.exr file write out
*bug in Maya/MacOS sRGB interpretation

*workflow miscellaneous for using a mix of 8bit and 32bit files
*workflow miscellaneous for using color managment

Mind you, it�s most likely we all know about linear workflow
but it is a pain in the arse to do it in Maya.

Please log a bug (or two) and keep us updated if you find the
sRGB source profile or ways to use a custom LUT.

Cheers

tim

On 23.01.2011 22:22, Gary Jaeger wrote:
> Thanks Phin. Did you see the image? I do understand the color management and linear workflow, but as far as I can tell I have two problems, at least on the mac side:
>
> 1. maya is saying it's using an sRGB profile but it's actually using a gamma 1.8 profile. I can get around this a few ways (convert the sRGB files in nuke or add a gamma .818 in maya)
> 2. maya is modifying the color somehow when it's writing a 32 bit linear .exr file. The color is correct for 32 bit linear tif files. the only way to solve this is to not use .exr
>
> btw I think using the lens shader and gamma nodes is no longer necessary if you're using maya's new built in color management. that was necessary before maya supported color profiles for file nodes
>
> On Jan 23, 2011, at 12:23 PM, Phinnaeus OConnor wrote:
>
>> I've just recently started using sRGB colour management system in Maya 2011 with the profile set to linear as maya and MR renders in linear colour space, The sRGB setting to compensate because our monitors work in sRGB.
>> If you are rendering, using FG or HDRI out to 8bit tiff, tga etc, then you need to hook up a mia_exposure_simple MR lense shader in to the camera and turn up the gain and knee settings to 1, bring the compression down to 0 and leave the gamma at the default 2.2. If you use the Physical Sun Sky light rig then it automatically puts in the mia_exposure_simple in for you, just remember to change theses settings.
>>
>> This should hopefully sort out your colour space problems, don't forget to select the linear option when bringing in textures too
>>
>> Remember If you are rendering to to 32bit exr etc, then don't forget to take off the lense shader before rendering.
>>
>> Hope this helps
>>
>> Phin
>>

[Gary Jaeger]

On Jan 24, 2011, at 2:09 AM, Tim Leydecker wrote:

Mind you, it´s most likely we all know about linear workflow
but it is a pain in the arse to do it in Maya.

yeah, the frustrating thing is that the framework they implemented works quite well. We just need more color profiles (see nuke grab attached) and some mechanism for creating our own. 

Please log a bug (or two) and keep us updated if you find the
sRGB source profile or ways to use a custom LUT.

yep, bugs filed. haven't found a way to make my own. strangely there is a way to Create a custom profile, but as far as I can see you're still limited to the existing choices. I can see no obvious benefit.

[Tim Leydecker]

Thanks for the info, Gary.

Yes, Maya is "almost �pefect" (tm tim leydecker, 2010, all rights
reserved, including the right to spell this �pefekt).

not funny.

Cheers

tim

On 24.01.2011 17:06, Gary Jaeger wrote:
> On Jan 24, 2011, at 2:09 AM, Tim Leydecker wrote:
>
>> Mind you, it�s most likely we all know about linear workflow
>> but it is a pain in the arse to do it in Maya.
>
> yeah, the frustrating thing is that the framework they implemented works quite well. We just need more color profiles (see nuke grab attached) and some mechanism for creating our own.
>
>
>>

[Ryan O'Phelan]

I would be interested in hearing a good reason to render in anything
other than linear space out of maya, especially in a nuke workflow.
I'm not saying you shouldn't, just that I can't think of a single
reason for it.

On Monday, January 24, 2011, Tim Leydecker <baue...@gmx.de> wrote:
> Thanks for the info, Gary.
>

> Yes, Maya is "almost 郡efect" (tm tim leydecker, 2010, all rights
> reserved, including the right to spell this 郡efekt).

>
> not funny.
>
> Cheers
>
> tim
>
>
>
> On 24.01.2011 17:06, Gary Jaeger wrote:
>
> On Jan 24, 2011, at 2:09 AM, Tim Leydecker wrote:
>
>

> Mind you, it愀 most likely we all know about linear workflow

[Phinnaeus OConnor]

Yes I agree ever since I've started to use it 'properly' in Maya and Nuke.

-and the fact its really easy to setup colour management in maya 2011 (under
windows and linux, OSX seems to have some issues)

----- Original Message ----
From: Ryan O'Phelan <desig...@gmail.com>
To: "maya...@googlegroups.com" <maya...@googlegroups.com>
Sent: Wed, January 26, 2011 2:44:06 PM
Subject: Re: [maya_he3d] sRGB profile in maya color management

[Gary Jaeger]

right, which is why it's so frustrating to hit these bugs. just the way it goes I guess

On Jan 26, 2011, at 6:44 AM, Ryan O'Phelan wrote:

> I would be interested in hearing a good reason to render in anything
> other than linear space out of maya, especially in a nuke workflow.
> I'm not saying you shouldn't, just that I can't think of a single
> reason for it.

. . . . . . . . . . . .

[Phinnaeus OConnor]

MR for Maya 2011 up to its usual tricks again, got some invisibily keyed in a
shot, works fine in the beauty pass when I batch render locally and to the farm.
When I then set off additional passes, AO, MV, ID mattes etc, there are random
objects missing with invisibility keyed. works fine when I preview render!

Doesnt make sense, has anyone else had this problem?

Phin

----- Original Message ----
From: Gary Jaeger <ga...@corestudio.com>
To: maya...@googlegroups.com
Sent: Wed, January 26, 2011 5:13:13 PM
Subject: Re: [maya_he3d] sRGB profile in maya color management

[Phinnaeus OConnor]

...I've managed to work around this problem by using material overide on layers
that use one shader, ie AO and MV.

But I need to render some multiple ID passes...

Does anyone know of a batch render preview script for M2011

Cheers in advance

[Tim Leydecker]

In the mR rendersettings, somewhere there, you can switch on:

"Preview Animation"

This�ll have Maya render the sequencelength, as set in the rendersettings,
right into the RenderView. Showing the 8bit image but dropping all the
rendered results into your "renderimages"/tmp folder, even if 32bit.

E.g., you could render locally, into your renderview and grab the
images from the tmp folder. No script needed.

Cheers

tim

[Phinnaeus OConnor]

Many thanks Tim, your a life saver :)))

[Tim Leydecker]

Just ran into the same thing not too long ago...

http://img1.brigitte.de/asset/Image/mode/mode-trends/Maenner-in-Badehosen/badehosen-5.jpg

cheers

tim