topic 16-bit TIF images not rendering correctly in Maya Forum

16-bit TIF images not rendering correctly

litote — Thu, 12 Oct 2017 16:26:35 GMT

When I render a .tif format image with Arnold in Maya and choose a 16-bit format (Format: int16 in Maya Render Settings-Common), instead of the default 8-bit, the rendered image looks correct in the Render View, but is darker in the output image -- more like a RAW coolur space image. I presume this may be because Maya/Arnold gets confused about applying 2.2 gamma correction to the output and so it looks more like a RAW linear colour space image.

I checked that the Gamma is set to 2.2 in Render Settings-Common tab.

Can someone confirm the same issue, or if there is some step I must take to output an image that looks right? I think this also happens with Mental Ray.

For 8-bit tif image renders the output looks correct as Maya seems to apply the gamma correction.

My only solution has been to apply a gamma correction in After Effects.

Re: 16-bit TIF images not rendering correctly

mspeer — Fri, 13 Oct 2017 11:55:35 GMT

Hi!

It seems you are using an older Version of Maya and Arnold (no Gamma Attribute anymore here with Maya 2017 and up and Arnold 4 and 5).

Arnold sets the default output for 16 bit files to linear (this can be corrected here, but i'm not sure if this can be corrected with your version)

Re: 16-bit TIF images not rendering correctly

litote — Fri, 13 Oct 2017 12:09:48 GMT

Hello,

The version I am using is 2017 update 4. What is the version/update number of Maya 2017 that does not show the Gamma slider for this setting (below), that outputs correctly as non-linear colour space?:

Render Settings-Common tab

Image format: tif

Format: int16

Arnold Renderer (I don't think it works properly in Maya 2016 with Mental Ray either).

With these settings I do see a Gamma slider set to 2.2. I would have assumed this would apply the gamma correction to convert the linear file to RGB, but it does not seem to apply any correction -- the image looks like a RAW/linear image. If I apply a 2.2 gamma correction in After Effects it look almost correct.

Thanks

Re: 16-bit TIF images not rendering correctly

mspeer — Sat, 14 Oct 2017 10:52:16 GMT

Hi!

You should use Color Management to achieve what you want (Arnold / Mental Ray) Color Space / Output Transform: "Use View Transform".

I can't test Arnold 4 anymore but you may read this:

https://support.solidangle.com/display/AFMUG/Gamma+Correction

You could try a reset of your preferences.
Rename the folder prefs in folder 2017 to something like prefs_backup, or to reset everything, the folder 2017 to 2017_backup (or even the maya folder to maya_backup). Maya creates new folders. Detailed at:
https://knowledge.autodesk.com/support/maya/troubleshooting/caas/sfdcarticles/sfdcarticles/Reset-Maya-to-Default.html

Re: 16-bit TIF images not rendering correctly

litote — Sat, 14 Oct 2017 13:56:41 GMT

Thanks, but it made no difference resetting my preferences.

I'm not sure where I should set my Output Transform. Should it be in Maya-Preferences-Color Management?

I tried checking Maya-Preferences-Color Management-Apply Output Transform to Renderer and set Output Transform: sRGB Gamma and also to Use View transform, it made no difference.

Enable Color Management is also checked.

Is there another update after update 4 for Maya 2017?

Re: 16-bit TIF images not rendering correctly

mspeer — Sat, 14 Oct 2017 15:01:34 GMT

Hi!

If it doesn't work correct for you in rendering and UI then maybe something is wrong with the installation.

You could try updating Arnold 4 to the latest version, install Arnold 5 or even re-install Maya.