How to put a Linear Workflow in practice with Cycles

Question

Most of you probably/hopefully heard of the Linear Workflow before. I've been doing a lot of research lately in regard to this topic and I am happy to say that I think I finally understood the theory of it. But my problem is that I am not really sure how to make use of it in practice now.

This is an image that shows the difference between linear and non-linear workflow:

Images from greyscalegorilla.com

To sum all this up, linear workflow helps you to get better and more realistic render results.

What I want to know is, how do I work in Blender with this technique? I read about Gamma Correcting my image textures before importing them into Blender.

Is it necessary to do that in Photoshop or can I simply add a gamma correction in the Node Editor? And, when do I add the final Gamma adjustment to my render, in post processing? It's just not clear to me at this point.

Here are some resources about the issue:

• http://www.loramel.net/blender_minutes/2009/01/linear-workflow-in-blender/
• http://greyscalegorilla.com/blog/tutorials/what-is-linear-workflow-and-how-can-it-help-your-renders-look-better/
• http://www.pixsim.co.uk/downloads/The_Beginners_Explanation_of_Gamma_Correction_and_Linear_Workflow.pdf

Answer 1

By default, Blender is a scene referred radiometrically linear reference space model.

This means that, when Cycles is selected as the renderer, values are radiometrically linear ratios that extend from zero to infinity.

The subject of color, color management, scene and display referred, and other such topics is immensely vast, far too vast for a simple answer here.

The short answer to your query however, is that Cycles is already a scene referred renderer, and no special effort is required to enable this aspect. More specifically, if you load an sRGB display referred image as a texture, it will be automatically linearized to display linear. While not scene linear, this permits textures to behave within a scene referred system.

Upon loading images in common formats such as JPEG, TIFF, PNG, etc. you should not adjust your image nor adjust your output. The linearization happens at the architectural level, and is correctly formatted for output.

To fully harness a scene referred model though, one should begin to round out their knowledge of color. A wonderful entry point might be the Visual Effects Society paper written by Jeremy Selan titled Cinematic Color: From Your Monitor to the Big Screen.

Answer 2

@poor This was my solution. Before adding an image texture into my shader, I did some gamma correction.

Don't forget to increase your gamma output after rendering under scene -> color management in your properties. I am still not sure about if it was the right way, but it did a good job at the end.