Compositing and Scene Referred Data

Compositing and Scene Referred Data

I always messed up my render in the compositor and finally I decided to find out what is going on exactly. I thought “I am going to ask Troy Sobotka (Developer of Filmic) so many questions that he will beg me to stop”. But he never stopped replying. So, many thanks to Troy, Gez and JKierbel on Twitter for continuous support. Here is the video Compositing and Scene Referred Data:

What is in the video

I made a video before (Blender – Post process EXR file in other applications) which didn’t make it to Blender Nation because it was not enough related to Blender. That was a kind of disappointment because in the video I discussed some very important topics:

  • Scene Referred Data vs Display Referred Data
  • Default view vs Display view
  • Why some nodes in the compositor are not working properly.
  • How to post process your EXR in other applications. And this was the issue.

Now, in this video “Compositing and Scene Referred Data” I decided to take another approach. Instead of post processing linear data in another application, I find out what exactly the issues are in Blender’s compositor. After a week of experiments and asking around, I figured it out. Here is what I discuss in the video:

  • A recap of the previous video that is related to Blender
  • Nodes in the compositor that are not designed for Scene Linear Data.
  • The meaning of basic operations like: add, multiply and power on a render.
  • The meaning of the values in the waveform, and when you right click on a render in the Image Editor.
  • Relations between Scene linear Data, Compositor, Exposure, View Transform Display referred data and Gamma.
  • Pivoted Contrast, so we can define the pivot of our contrast
  • Cryptomatte and other mattes vs hold outs
  • Multi Layered Pivoted Contrast

Why the video Compositing and Scene Referred Data is important.

One of my objectives is to help the Blender community just because I am a Blender user myself for 6 years. And I know the potential of Blender and I recognize the urge of creating. Many Blender users dream about making a career with Blender somehow. Now, Blender is a mixture of tools. Some tools are designed for display data while they are operating in scene linear data. The reason that this is so, is that Blender worked for many years with a default transform view which is not good to represent Scene linear data on the screen. The result of that is the Blender developers didn’t realize, when they got their inspirations from Photo Editing programs, that these tools are not working properly on Scene linear Data. Namely: you don’t see it when you use the wrong view transform.

And , after 4 years of Filmic in Blender, we still see tutorials that doesn’t respect scene linear data. Many users still don’t realise what is going on exactly. I hope that this time, the video will reach more users. Good thing, is that I see already a good amount of interest, but often the right people have to discover it.

On the other hand there are other very good tutorials, so this is not the only video. But each video is unique and uses another approach. If you want contribute info for the next video (part 2), you can also use the post on Blender Artists Forum.

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