What is the best way to save an EXR file (gamma)?

[Pollysong]

Hi.

 

I'm playing around with LWF in VRay and have a simple question (that applies to any renderer, I guess). Is it bad to save an EXR with gamma 2.2 burnt in or do I still get enough "bright data" to lower the exposure if I want to?

 

If I save the EXR with gamma 1.0, what is the best way to achieve the gamma 2.2 look in PS? Is it enough to add an exposure adjustment layer and increase the brightness or do I need any other tricks to get the exact results as when I check the sRGB button in VRay FB?

 

Sorry about the noob questions, I couldn't find any answers when I searched the forums.

[notamondayfan]

Are you saving straight from the Frame Buffer, or from out Render Output?

 

As far I as know / understand, gamma isn't baked into floating point images (HDR, EXR, etc) so long as you save as either 16bit half float, or 32 bit.

 

As for getting it to look right, you would be best using a compositing program, like After Effects, so you can quickly adjust the import / workspace / colour profiles easily, and adjust exposure properly, then export to photoshop.

[Pollysong]

I set VRay to auto save an EXR in the Frame Buffer rollout (i think, I'm rendering so I can't check). When I load the EXR in PS I choose to apply the sRGB colour profile, but I still get different results depending on what gamma I've set in Max's LUT/Gamma settings. If I set bitmap output gamma to 2.2, I get the much brighter 2.2 gamma as a default and if I set bitmap output to 1.0, I get the dark 1.0 image in photoshop. So I guess that is my question, does it really make a difference or is it just "on the surface"?

[notamondayfan]

First disable the vray frame buffer, and use the Render Output to save your exr, and click the setup button and check you are saving as either 16 bit half float or 32 bit.

[Pollysong]

Ok, I'll try that. What is the difference? Do they save the image in different ways?

[notamondayfan]

it use to be that if you saved from a frame buffer it wouldnt save as a floating point. I dont know if its changed in recent releases, but I always save out through the Render Output anyway.