Clear your mind.

Grasp this very important concept.

The display you stare at all day is intentionally non-linear. It is done this way for many reasons, but we don't need to know them. All we need to recognize is that 100 is not half the brightness of 200. It is nonlinear.

Read this:

http://en.wikipedia.org/wiki/Gamma_correction

The purpose of gamma correction has NOTHING to do with renderers and was invented decades ago.

The purpose is this:

Quote - Gamma encoding of images is required to compensate for properties of human vision, hence to maximize the use of the bits or bandwidth relative to how humans perceive light and color

It is a way of compressing more useful (from a human perception point of view) information into 8 bits. Otherwise the dynamic range (smallest representable change versus largest representable brightness) would be much smaller.

Failure to understand its role in computer displays and image technology is why renders look bad. The process of recognize the role of gamma encoding in rendering workflow, how our inputs colors are represented, converted to linear, operated on, and the result converted back to gamma encoding, is a common reason renders look wrong. Taking all of that into account is how we get realism because naively pretending that the pixels in an image are linear is - well - naive. Taking gamma encoding (not correction - but the way numbers are represented in 8-bits) into account in your workflow is called "linear workflow" and it's super important for equations to actually produce realistic images.

---

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)