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Normal Maps and Color Correction

Posted: Tue May 23, 2023 9:53 am
by Andreas_Resch
I stumbled over another thing where I don't know if it's a bug or if I'm misunderstanding something.

When I insert a Color Correction node in between the normal map (RGB Image) and the Normal socket of the material, its look changes significantly although I did not adjust any settings in the Color Correction node. However if I do the same thing an plug the output of the Color Correction node into the Albedo socket of the material, the result looks unchanged (as it should be). Below is a test scene that shows the effect. In the top row the Color Correction node is places into the Albedo socket, in the bottom row the node is plugged into the Normal socket. You can also see the node layout in the second image. Maybe somebody can solve that problem for me. Cheers.
NormalMap_01.jpg
NormalMap_02.jpg

Re: Normal Maps and Color Correction

Posted: Tue May 23, 2023 11:18 am
by ShivaMist
Could it be related to the fact that you are using a Gamma Value of "2.2" in your Image Texture node ? Usually an info map has to be fed to Octane as with a Gamma Value of "1", you can also choose 'Non-Color Data".

Re: Normal Maps and Color Correction

Posted: Tue May 23, 2023 11:21 am
by Andreas_Resch
It's a normal map so it's colored and the Gamma value should be fine at 2.2. But it does not matter. At a Gamna value of 1 the situation is the same. Thanks.

Re: Normal Maps and Color Correction

Posted: Tue May 23, 2023 12:19 pm
by linograndiotoy
I would never change the colors/brightness or anything in a normal map, since the color value of the image are exactly what the normal node is expecting to receive.

Re: Normal Maps and Color Correction

Posted: Tue May 23, 2023 12:24 pm
by Andreas_Resch
That might very well be. But sometimes tweaking the normal map a bit makes sense. It's up to the creator to decide. And if it's just to lessen or strengthen the effect. So the question still stands. Why is the Color Correction node in front of the Normal socket acting differently? Like this it looks like a bug.

Re: Normal Maps and Color Correction

Posted: Tue May 23, 2023 12:33 pm
by linograndiotoy
One node that makes sense to be used with a Normal map is the Multiply node (Add Texture is another). The color correction node is not intendended for normal maps and shouldn't be used in this case.

Re: Normal Maps and Color Correction

Posted: Tue May 23, 2023 12:45 pm
by Andreas_Resch
If there's a lackluster workaround, then let's not fix it. Not my kind of philosophy, but what can you do. Let's add another workaround to the list.

Re: Normal Maps and Color Correction

Posted: Tue May 23, 2023 12:51 pm
by linograndiotoy
There's no workaround to add in this case. Again, color correcting a Normal Map is not something anyone should do. Simply it doesn't make any sense.
The Node works as it should with any other kind of texture map.

Re: Normal Maps and Color Correction

Posted: Tue May 23, 2023 1:10 pm
by Andreas_Resch
Well. The thread is here now. People who scratch their head about this issue, might find it and see how to avoid it. Once the bump map scaling is fixed I'll go back to using bump maps anyway.

Re: Normal Maps and Color Correction

Posted: Tue May 23, 2023 1:31 pm
by ShivaMist
It's a normal map so it's colored and the Gamma value should be fine at 2.2. But it does not matter. At a Gamna value of 1 the situation is the same. Thanks.
I might be wrong, but the way i understand it, it's still Information data, not Color That You See data, so applying a 2.2 gamma correction would alter the look of the normal map.
Andreas_Resch wrote:Well. The thread is here now. People who scratch their head about this issue, might find it and see how to avoid it. Once the bump map scaling is fixed I'll go back to using bump maps anyway.
I'm not sure that the bump map scaling has ever been acknowledged or is being worked on. Someone in the C4D forum talked about it (it think it's Ssmolak) but nobody seems to either acknowledge the issue, or find that it is an issue, same for your topic. Nobody has answered your last post in your topic talking about that.. so i guess maybe one day we will have an answer :)