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misterwolfy
11-24-2009, 05:57 AM
32 bit HDR files are "linear" as I understand it. Making them perfect for use in a linear work flow and 3d rendering.

My question is: when creating an HDR, what is the significance of the ldr images' gamma? Can you make a good hdr with bracketed images that are set at 2.2 gamma?

In the process of revising my work flow to linear, so I am still at the learning stages on this. Thanks for reading!

beaker
11-25-2009, 12:42 AM
32 bpc files can hold any colorspace you want. It is simply a container. It is preferred and assumed by some applications though that information inside it is stored in linear space. It can store gamma 2.2 if you want.

misterwolfy
11-25-2009, 12:56 AM
Thanks for your reply. In regard to using the HDR for reflections and physically accurate lighting inside a 3d package, is it important to set the source images to linear color space, to match the linear color space of the 3d scene?

misterwolfy
11-25-2009, 01:00 AM
Or do I need to reverse the gamma of my HDR images using gamma .45 before rendering with HDR images created from source images with a gamma of 2.2?

Aneks
11-25-2009, 03:05 PM
Thanks for your reply. In regard to using the HDR for reflections and physically accurate lighting inside a 3d package, is it important to set the source images to linear color space, to match the linear color space of the 3d scene?
if you are trying to do IBL with the images then you are better of using linear colourspace images. Make sure to keep them linear when capturing stills and constructing the spherical image. It is also better if you make your textures linear rather than relying on an inverse framebuffer gamma.


Remember in Maya that, by default, all the colour pots in shaders are gamma corrected also. I think Vray for Maya and the latest renderman have a linear workflow option that fixes this for dedicated shaders.

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