EXR needing Gamma Adjustment

[Infrared digital]

When I save out exr's from VRay they need gamma adjustment in Photoshop and AE of 0.4545. Jpegs which are saved out are fine.

Any idea whats wrong ?

Thanks

N

[Morbid Angel]

check to see if your bitmap output gamma is set to anything other then 1.0

[bob-cat]

Also make sure your colour mapping gamma value = 1.

[muzzy]

It is normal if you dont use VFB and gamma correction/or LWF setups.

[brobins]

I think the 'Dont affect colours (adaption only)' check box in the Colour Mapping Roll-Out solves this...

[ruffstuff]

We use gamma 2.2 when working in max and EXR's are outputted perfectly for working in AE CS3. Photoshop handles EXR's differently than AE and they look double gammed.

Please don't change anything in the way EXR's are gammed.

[Infrared digital]

Unfortunately, none of the above have worked.

[simmsimaging]

I think this is normal for Photoshop and exr files. Just set your gamma to 1 on save and adjust To .45 in Photoshop. You can create a Photoshop Action/batch script to apply the correction if you want. Or use .hdr instead

[Morbid Angel]

by defualt photoshop should apply a gamma 2.2 to any float image. So if you save the exr in linear 1, then open it in photoshop and you will get 2.2 automatically. If you have to apply .4545 back onto it, this means your exr already has gamma. If you go to your color mapping options and if you have gamma 2.2 set there, check for adaptation only. This will not apply gamma 2.2 to the image, rather only to samples. Also make sure you are writing out exr via vray framebuffer output.

[simmsimaging]

Dmitry: do you mean "adaptation only" should be check on? I have that on all the time, which I understood to be correct for proper linear workflow. Should that be off? I definitely have to apply the .45 gamma everytime, and I only use the VFB or the vray dialog for saving the files.

b

[Morbid Angel]

adaptation only should be on. This way the sampling will be applied to image at gamma level, but actual image will be linear. Can you maybe attach an example scene with your settings in it, so we can have a look?
it can just be ball on the plane with a light or whatever.

[simmsimaging]

Attached is a screen cap of the settings. I'm pretty sure this is a typical linear workflow. However this will create .exr files (saved with gamma at 1.0 from the VFB) that require gamma correction in Photoshop. If I set the gamma to 2.2 they are double-gammad in Pshop.

b

[Morbid Angel]

the reason i asked for an example scene is because there is more then one place where gamma can be affecting your image save.

[simmsimaging]

Okay - scene below.

Where else would there be a gamma setting though?

b

http://www.simmsimaging.com/upload/f...xStart.max.zip (25.52 KB)

[cecil gittens]

I think PS is doubeling the gamma, when ever i saved an exr file, i saved a jpeg file also. the jpeg file has the correct gamma, so i matched the exr gamma to the jpeg gamma in photoshop. That means i have to reduce the exr file gamma to 50%.
Maybe you can try this, (i havent done so as yet) save the file as a vrimg then use max file viewer to view it to see if the gamma is correct.
convert the file to exr and view it again. if it look correct then the problem is in Photoshop.

Cecil