Read this. Pixar uses linear workflow now and so do we.

http://renderman.pixar.com/view/LinearWorkflow

Understand it well, or you're not playing with the pros.

Quote - Linear workflow refers to a rendering workflow in which image gamma is carefully taken into account in order to assure proper light computations in a render.

Image gamma <<<<< this is the key - when we work with images or computer colors, we must understand the role of gamma encoding in what those numbers mean. They don't mean what you think they mean.

We all agree that 14 is brighter than 7, and that 57 is brighter than 50. But by how much? That's where the difference comes into play.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)