How to Use Color Management in Maya
Color management in Maya is undertaken by using the render view and render settings. The color profile that is used for inputs and outputs when rendering can be controlled. Many different elements within the scene are associated with a color profile, such as mental ray file output passes, mental ray textures, render passes and file textures. All color management can be enabled by going to the common tab under the render settings. Enable color management must be highlighted within this common tab. Be aware that by enabling this color management, the processing time may increase.
There are 3 main elements of which color profiles are associated. The file texture and mental ray texture node will show the color profile that is attached to each of the textile sources. The render pass will show the color profile that is used when the render pass is written to the disk. The mental ray output pass node will show which color profiles are used when the image is burned to disk.
Look Up Tables (LUT)
LUTs can be used to control many elements of color management. The LUT will control the gamma, tone mapping, exposure and contrast. The LUT will be a table that contains lists of numbers that can change one color space into another. So, the color scale can change from linear to logarithmic. These are needed because not every image will respond to light in the same way. Which scale is used will depend on the necessary acquisition format.
Film will have a non linear response to light, as it uses a logarithmic scale. Film is much more sensitive to shadow than light. Most computer work will use a linear scale, as most 3D renders will be linear. So, in order to get a logarithmic scale effect, a LUT will be used to simulate how the image would look if it were captured on film.
The exposure LUT works by F-stop, gain or printer lights. By increasing the F-stop amount by 1, the luminance of the image will double from the original. This works as in a logarithmic scale. Printer lights work in a similar fashion, though it will take many more to achieve the same effect as the F stop.
Gamma correction is normally used to control the contrast. By moving the adjustment along the LUT scale, the contrast can change to be very bright or dark. The software has a default value of 1. However, this should be set similar to the computer display value. Now the image will look as it should on the monitor. Most monitors will show images as too dark, and by changing the gamma, the image will be brightened before it is displayed.
Maya will produce images in a high dynamic range (HDR). However, the human eye cannot see in HDR; it uses low dynamic range (LDR). The HDR images will need to be converted to LDR, as HDR images are frequently thought to be over exposed. Tone mapping is used for this conversion. Once the image has been converted, it can be displayed on a computer screen.
There are 2 different options for tone mapping: mia_exposure_photographic and mia_exposure_simple. The simple version will scale all the values to within the 0 to 1 range. Therefore, if the minimum range is 0, this will stay as 0. However, if the maximum value is 10, then this will be changed to 1. The photographic option is more advanced. The advanced changes will convert the luminance’s form pixels to candela per square meter.