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What I'm working on...

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"8 bit images are encoded with a gamma but not in an EXR image"

Does that mean the values are actually changed in the 8 bit mage?

If I render a 50% gray in a TGA and an EXR and load those into a paint program and sample the color values, both will say they are 128, which is 50% gray.

Where is the gamma correction happening?

 

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The gamma correction happens for viewing on a monitor.  An EXR image doesn't store gamma correction because there is nothing to correct...it is a linear image by default.  8bit images are being corrected to be viewed the same.

 

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EDIT

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If you render your 8bit image using the same gamma setting as the EXR image (it is always 1.0 gamma), they shouldn't match.  However, if you render the 8bit image at 2.2 gamma, they should match.

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Here are three renders to compare.  I included the original OpenEXR in the zip (16bit 1.0 gamma), which I then used Black Magic Fusion to convert to 8bit 2.2 gamma (PNG), a render straight to 8bit 2.2 gamma (PNG) and an 8bit render straight to 1.0 gamma (PNG).  The render straight to 8bit 2.2 gamma does match pretty closely the 8bit image converted from a 1.0 gamma OpenEXR, but the 8bit image rendered straight to 1.0 gamma does not.  This is because the 8bit image is being "corrected" as if it were a 2.2 gamma image by your computer/monitor.  The two other PNG's are also being "corrected", but they have the expected gamma curve of an 8bit image while the 1.0 gamma PNG does not.

 

Hope that helps.

1_0_gamma_EXR_converted_to_2_2_gamma.png

2_2_gamma_rendered_at_2_2_gamma.png

2_2_image_rendered_at_1_0_gamma.png

 

Gamma_images_10_01_2019.zip

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I have posted an updated set of images for the Smoking Area  here.

I realize I've taken forever to get it to this point. I'm trying to get out of my own way and actually finish some of this.

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I've been doing a lot of experiments, but don't have anything I can show yet.  So, I decided I needed make another "stay alive" post.  I think I'm close on what I'm messing with, but I always think that.

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Just another "stay alive" post.  I still don't have anything worth showing, but I have gotten past a few experiments.

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