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Krion

How to render 16 bit EXR from Houdini?

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Posted (edited)

Hi,

 

I was wondering how I can render 16 bit EXR images (with CryptoMatte) from Houdini.

And how I can check on my Mac how much bit current renders are. 

The info panel of Finder says about my recent render "Generic HDR Profile", so I guess it is 32 bit?

5d9b387db5bca_Screenshot2019-10-07at15_06_10.png.b58e73e612697062b56e87352b3badf8.png

 

Thank you! 

Edited by Krion

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Use houdini's iinfo command line tool. It'll give you more information about any image Houdini recognizes.

> iinfo test.exr

File:             ./test.exr (OpenEXR format)
Resolution:       2048 x 2048

C (r,g,b):
  Data:           16 bit float
  Color Model:    RGB
  Channel Depth:  16 x 3 (48 bpp)

A:
  Data:           16 bit float
  Color Model:    Single Channel
  Channel Depth:  16 x 1 (16 bpp)

Format Specific Information:
    Image Type:          Flat
    Compression:         zips
    Storage:             Scanline
    Comment:             none
    Created:             2019:09:27 12:49:22

 

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Posted (edited)
13 minutes ago, malexander said:

Use houdini's iinfo command line tool. It'll give you more information about any image Houdini recognizes.

Where does the image have to be located? 

When I paste the Pathname there it doesn't do anything.

And when I put the exr in the same folder as the hip and just use the name it doesn't do anything also.

When in Home folder I get "Can't open iinfo"

Edited by Krion

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You need to run houdini_setup in the shell. But it might be easier just to open the image in COPs with a File COP and check the MMB node info.

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If you're in Houdini, you can open a Shell (Windows->Shell), which is basically a shell that includes Houdini environment settings.  From there, you can run iinfo, and whole mess of other useful scripts, regardless of which directory you're in.  Meaning, you don't have to move your files anywhere special to run.

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Allright. 

The middle mouse click will do for now. :) 

I see that my image is in most planes 16bit, but in the CryptoMatte planes 32bit. 

5da0d3bdea62a_Screenshot2019-10-11at21_07_15.thumb.png.07f4041efbf4fb713aed621c03936f61.png



But I guess that makes the image a 32 bit image, right? (I guess tilex and tiley stand for the amount of bits?)

5da0d39a4d4c8_Screenshot2019-10-11at21_06_35.png.74191a1eae51c665b96a312663c5848a.png



Anyways: the reason I am asking this is because I wanted to check if the amount of bits may be the reason I have these weird color transmutations with different apps if I use an exr. I describe this problem partly here. If anyone wants to help with that, that would be greatly appreciated. :) 

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EXR is a linear colorspace format. It must be converted to a non-linear colorspace when viewing so that it looks right. When you load it into Houdini, you basically get it displayed with a 2.2 gamma (or, if using OpenColorIO, some colorspace like sRGB or REC709). I couldn't tell you what Finder is doing.

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Thanks @malexander,

 

Your comment made me research what that means. 

Just for a brief mention:

A feature in Affinity called a OpenColorIO adjustment layer saved me with this. 

For some reason this color profile (lin_p3dcl) converted the image back to how it was in Houdini.

 

5dc1b23a26e07_Screenshot2019-11-05at18_29_52.png.be59116cb9187228af3c7b2f75f95855.png

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