[help] EXR files and photoshop

[harnstein]

Good evening all,

i could not get satisfying information about saving EXR files from Vray to import them to Photoshop. I'm at the very beginning of this workflow.

There is a great potential when you can edit different channels seperately.

Can someone give me a short overview about the steps in that process or provide some useful links?

Thanks in advance

_h

[holmes1977]

Hi

Im interrested in the answer to your question as well.
I had a few problems with this a year ago.

have you tried posting something on the ASGVIS forums?

http://forum.asgvis.com

Your most likely to get an answer there.

[andybot]

Which version of vray are you using? AFAIK The exr format only saves transparency in addition to the color output. The only way to save additional channels to exr is by using vrimage format and converting using the vrimg2exr converter. Apparently, vrimage doesn't work in the current build of vfsu (1.49.01 does not produce a vrimage that can be converted to exr.) Using the converter is somewhat more complicated that I have time right now to explain. If you don't know how, there are resources out there on how to do the conversion.

*edit - I'm assuming you are trying to save as a vray raw file. Otherwise, channels save the same as any other format (separate file is written) if you are saving the image after the render is complete.

[harnstein]

Thanks for your answers!

I use vray 1.48.89 (as to see in my profile as well ) in the office. I just spend some time in this kind of research when i have a few minutes without work.

I surely already did read about that on openexr homepage and proexr hompage and some other places as well.

What i got is that 32 bit format is unnecessary, too big with not much improvement to 16 bit.
A correct 16 bit image file has a lot of information, eg. you can see a lot of details in the dark when over-exposed which you cannot see in a "nomal" picture. From that you should easily be able to make some kind of what people think of when they hear "hdr-picture": a picture with all areas detailed, not too dark and not too bright.

I had a look at the sample psd-file from fnord http://www.fnordware.com/OpenEXR/ (at bottom of that page) and was impressed about the different channels and about handling them. Eg. increase only lighting-channel-exposure. But i couldn't get this to work from my exr files.

Andybot, you're right- i doesn't matter what file format you use. If you choose your VFB channels and save that file afterwards, you get a file for each channel. (Probably exr and hdr files contain more information than jpg or png.)

I figured that out before. The misunderstanding was, that i expected a single exr file which i could open in ps and get the result as proposed in the psd-file from fnord.

If i get it right now, the mistake (as usual, me) was in the blending mode of the layers inside PS.

Import eg. files called: Model, Model_diffuse, Model_lighting, Model_alpha.

Add the Model_alpha as a layer mask to Model. Add Model_diffuse, Model_lighting as clipping mask to the first (bottom) layer. Change blending mode of Model_diffuse to "multiply" and blending mode of Model_lighting to "linear burn".

That should make things right. Now you can edit the different channels according to your needs!

Thanks for your attention

Best regards, _h

[harnstein]

.. and that is great!

Its like playing with a new toy

[andybot]

glad you found what you needed

That is indeed the case with channels - vray gives you separate files. You then have to combine them yourself in PS. The only exception to that is using vrimage, which combines all the channels in one file. From there you have to use the converter to get an exr file.