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CMSTestPattern

This node generates calibration patterns for color management. You should run the output of this node through a color management node and then render the result with a GenerateLUT node. This way, you can produce 1D and 3D lookup table (LUT) files for various programs:

• 1D LUTs assume that the primary color channels (red, green, and blue) are independent, and the output for a particular primary color (for example, red) only depends on the input value of that channel (rather than the values of all three channels). For each input value, there is one output value. 1D LUTs are represented by a curve. They are useful for quickly creating an image for viewing purposes, using less processing power, but they cannot be used to adjust saturation independently of brightness.

• In 3D LUTs, the output values of each primary color channel are calculated based on the input values from all three channels (red, green, and blue). For each input value, there are three output values. This is represented by a 3D grid or cube. 3D LUTs can adjust saturation and brightness together, and are very useful for emulating a particular known look, such as Cineon.

Inputs and Controls

Connection Type	Connection Name	Function
Output	unnamed	Add an arrangement of Nuke nodes that do the color correction you want your 3D LUT to do. Then output the result using a GenerateLUT node. Alternatively, you can insert a Write node after the CMSTestPattern node, write the image out, grade it in another application, and read the result back in using a Read node. Then output the result using a GenerateLUT node.

Connection Type

Connection Name

Function

Output

unnamed

Add an arrangement of Nuke nodes that do the color correction you want your 3D LUT to do. Then output the result using a GenerateLUT node.

Alternatively, you can insert a Write node after the CMSTestPattern node, write the image out, grade it in another application, and read the result back in using a Read node. Then output the result using a GenerateLUT node.

Control (UI)	Knob (Scripting)	Default Value	Function
CMSTestPattern Tab
RGB 3D LUT cube size	cube_size	32	Enter the cube size to use for the test pattern. The cube size defines the size of the LUT cube on the xyz axes with higher values increasing the number of colors. In reality, you would be unlikely to use a cube size greater than 128 and the test pattern is automatically clipped above cube size 444.