Different Ways to Add Gamma in Your Renders

7/27/2019 Different Ways to Add Gamma in Your Renders

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Different ways to add Gamma in your renders

Lesson byCiro Sannino - Authon May 17, 2012, filed in:V-Ray Tutorials

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Every real device to take pictures adds gamma.

We actually are producers of images and we need to correctly setup the gamma in 3ds Max, inorder to imitate the behavior of real cameras.

In 3ds Max the options we have to add gamma are various:

1. Gamma in output / preferences2. Gamma / color mapping3. Dont Affect colors / color mapping4. sRGB button /V-Ray Frame Buffer (VFB)

Every option in this list affects gamma.

As you can understand we cant use all at the same time!

We have to choose a combination to just adds 2,2.. once!

Im going to show you how many combinations are possible and youll see just one way is thecorrect one.

COMBINATION 1 : Gamma in.. OUTPUTfollow the green arrow

- Gamma in output /preferences = 2,2

- Gamma in color mapping = 1,0

- Gamma in VFB (sRGB button) = disabled
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Brief Explaination:Youre adding 2,2 to the final image. But in this ways will youll get artifacts in the shadows.

The reason is that youre just adding a fake gammanot good

COMBINATION 2: Gamma in sRGB button (follow the green arrow)

- Gamma in output / preferences = 1,0


- Gamma in VFB (sRGB button) = enabled
http://www.cg-blog.com/wp-content/uploads/2012/05/combination2-srgb.gifhttp://www.cg-blog.com/wp-content/uploads/2012/05/combination1-gammaoutput1.gifhttp://www.cg-blog.com/wp-content/uploads/2012/05/combination2-srgb.gifhttp://www.cg-blog.com/wp-content/uploads/2012/05/combination1-gammaoutput1.gif


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Brief Explaination:

Youre adding 2,2 with the sRGB button but its just a preview ofgamma. When you save the

image the gamma is not added, so youll see a different image out of 3ds Max! wrong usage!

COMBINATION 3: Gamma in.. Color Mapping (perfect)follow the green arrow



- Gamma in VFB (sRGB button) = disabled

Brief Explaination:Youre adding gamma 2,2 during the computation: thats fine! Simple and effective.

COMBINATION 4: Gamma included but not visible (for compositing)follow the green

arrow


- Gamma in color mapping = 2,2/ dont affect colors = enabled

- Gamma in VFB (sRGB button) = enabled (for preview)
http://www.cg-blog.com/wp-content/uploads/2012/05/combination3-gammaincl.gif


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Brief Explaination:Youre adding gamma 2,2 during the computation

Dont affect colors hide gamma but avoid artifactsUse sRGB button just to have a preview

This way is perfect if you want to save in EXR or you want to add gamma in compositing with

more layers. In these case sRGB button is really useful to preview how the image will looks afteradded gamma in compositing.

CONCLUDING

Resuming all combinations:

Way1 produces artfacts Way2 is just a wrong usage of sGRB button! :-\

Ways 3 and 4 are correct but it depends on your operating mode:

Way3 is simple and ieffective to add gamma during the render (my favourite) Way4 is for adding gamma in a different moment from the rendering (compositing)

I showed you also Way1 and 2 to let you avoid these ways!

*

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http://www.cg-blog.com/wp-content/uploads/2012/05/combination4-dontaffect.gif


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Note 1: If your image is correct in 3ds max but really brighten in photoshop the causes are 2:

1) check output value in preferences: it must be 1,0

2) you just used Way2

Note 2: Of course if you use gamma in color mapping + gamma in output + sRGB button

youre completely wrong. Gamma added will be 2,2 + 2,2 + 2,2 and your image will resultscompletely washed out! Every image need just 2,2 once.

Note 3: Always use V-Ray Frame Buffer

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Different Ways to Add Gamma in Your Renders