Tone & Gamma
Gamma and tone mapping introduce the issue of colour calibrating, tone control and lighting exposure. This post is a quick overview of what Gamma and Tone mapping can offer.
Some terms we’ll need to define:
Gamma: is a nonlinear operation to code and decode luminance in video or still image systems. There is a whole science to it and to start reading, introduce yourself to a wiki article.
Tone Mapping: is a process of mapping colours/tones to reduce strong contrasts and map them to the displayable range and maintaining image details.
Monitor Calibration: a process to measure the colour response of a device and match it to a known colour space. There are devices on the market from consumer to professional available. This process is important we investigate and research the impact of gamma nd tone correction. A good article on gamma and how it affects 3D rendering applications (3DSMax & Vray highlighted).
An important aspect to watch for when rendering is the tone/gamma distribution in the image. A good aspect to watch for is the amount of contrast between the lights and shadows, where typically, it is natural to have very strong contrast between shadow and lighter areas from the render.
A lot of people have the let down when they post a render without doing tone control, and get feedback that is confusing. So, typical users may go back to the render application and add more lights, lower light intensities etc. However, tone and gamma correction will be an easier solution.
Tone & Gamma Corrections – Yves Poissant