saving EXR and gamma settings

[liorsturlesi]

Hi,

When i'm saving In EXR format in 3dsmax- 32 bit (2016+vray 3) and open the file in PS, i'm getting the file like png (as with no background) for some reason.

Also all pictures saved as very dark ones - something with the gamma is wrong - in the past vray version all you have to do is adjusting the gamma on the preferences tab, is it necessary to make an adjustment in other places too (the way i bypass the problem now is saving the gamma override as 2.2 in the saving pictures dialog just before hitting the render button but i'm not sure it's the right solution.

 

Thank you in advance.

Lior.

[Francisco Penaloza]

When opening any EXR in Photoshop, hold the Alt key and click open, this will promp an option windows that will ask you if you want the Alpha channel to be transparent or as separate layer.

Photoshop is not flexible enough to use EXR by default, you could buy proEXR plugin that will let you use more features of that file format. Also by default Photoshop will read your EXR as 2.2 gamma. If you are getting a darker image, then you have other problems.

 

if you setup your 3D Max and VRay by default you should not have any gamma issue. Unless you changed something or are using some weird crack version, Gamma should be a thing of the past, no need to touch it.

 

The only thing you could change is within VRay to choose to bake the gamma and/or color mapping in the image or use it a linear. Default is linear.

When you save your image within VRay pannel, you can select in the exr option to save the image with alpha as separated channel.

[liorsturlesi]

thank you Francisco, but pressing the ALT doesn't open any dialog as you mentioned. Are you sure it's an alt ?

[Francisco Penaloza]

Sorry, that was a mistake I did while typing. When using the proEXR plugin you can hold Alt key and click open to get the options.

[liorsturlesi]

thank you - it's working now.

Regardless that issue for some reason i still suffering from the gamma dark images output (i didn't change a thing in the defaults ) - very annoying..

[TomasEsperanza]

thank you - it's working now.

Regardless that issue for some reason i still suffering from the gamma dark images output (i didn't change a thing in the defaults ) - very annoying..

 

If you were comping your EXR's you'd want them to remain linear, and as such they shall appear too dark. But you want to do the maths on them like this. To see what you are getting as a result, you would put a gamma of 2.2 on top of the comp. In PS I would do this with a levels adjustment layer at the top of the stack. The mid point is set to zero by default, but you can type in 2.2 (or 0.45 if required) to adjust the gamma output.

 

If you're not concerned with linear compositing, it's still useful to know.