The Adjustments shader allows you to adjust the color levels of your rendered image.
Hue
Changes color in an image: greens can become yellows, reds can become blues. The value specified here is the number of degrees to rotate on the color wheel. The default value is zero and causes no color change.
Brightness
Adjusts the overall brightness of the color. Negative values make the color darker and positive values make the color brighter. The default value is zero and causes no color change.
Contrast
Adjusts the variation of brightness in an image. Negative values shift the colors towards a neutral gray, while positive values make brights brighter, and darks darker. The default value is zero and causes no color change.
Saturation
Adjusts the “purity” of a color. Negative values mix in grays to make pastels and lower the colors' saturation, while positive values remove grays and raise the saturation. The default value is zero and causes no color change.
Lightness
Very similar to Brightness, it adjusts the overall lightness of a color, but uses a slightly different technique. Negative values bring the color to black and positive values bring the color to white. The default value is zero and causes no color change.
Levels
These options allow you to adjust the overall lighting levels of your image by darkening or lightening shadows and highlights.
The value for each of the RGB channels for each pixel is adjusted on output according to where it falls within the input range:
• Values between Input Low and Input High are remapped to a proportional value between Output Low and Output High.
• Values below Input Low are remapped to Output Low.
• Values above Input High are remapped to Output High.
Input High
Sets the highest value for the input range. You can set values between zero and 255.
Input Low
Sets the lowest value accepted within the input range. You can set values between zero and 255.
Input Shift
Input Shift will gamma correct the color. A value of 1.0 corresponds to no gamma correction.
Output High
Sets the highest value for the output range. You can set values between zero and 255.
Output Low
Sets the lowest value for the output range. You can set values between zero and 255.
Render Tree Usage
This output shader isn’t used directly in the render tree; rather, it is applied using a pass’s shader stack. For more information, see Applying Shaders to Passes [Rendering].
