Color managed linear workflow

The following describes how to set up a color managed linear workflow in Maya.

A linear workflow is necessary for photorealistic rendering because any output display (for example, a monitor) has a signature response curve that affects the way color is displayed. As a result, to produce color that appears correct to the human eye, a color correction has to be applied to an image. Therefore, you must reverse this color correction before lighting and rendering so that rendering calculations can be made with the correct color values, and then color correct the resulting image again before it is displayed, so that it appears correct. This results in much more realistic lighting and compositing with greater falloff and softer highlights, as illustrated in the image below.

Setting up a color managed linear workflow

1. Select mental ray as your renderer (Render > Render using > mental ray).
2. Select Window > Settings/Preferences > Preferences, and under Rendering, select 32-bit floating-point (HDR) under Render view image format.
3. In the Render Settings: Common tab, select Maya IFF or OpenEXR as your image format.
4. In the Render Settings: Quality tab, under Framebuffer, select RGBA (Float) 4x32 Bit as your Data Type.
   NoteWhen rendering an image using the .exr file format, you must change your framebuffer type to 32-bit float or 16-bit half float. Otherwise, your image will be clamped to [0, 1].
5. In the Render Settings: Common tab, under Color Management, select Enable Color Management.
6. Select sRGB as your Default Input Profile. For more information on color profiles, see Color Profile .
7. Select Linear sRGB as your Default Output Profile.
8. In the Render View window, select Display > Color Management.

   The defaultViewColorManager Attribute Editor appears.

9. Select Linear sRGB as the Image Color Profile.

   This is the incoming format of the rendered image.

10. Select sRGB as the Display Color Profile.

    This is the desired display color space.

11. Render.

Other important notes:

• The resulting linear image from a batch render must be color corrected for final display, and this is usually done at the end of the compositing process. Choose sRGB for your output and input profile if color managed images are intended to be used immediately after rendering without further adjustment.
• Scalar or single channel texture images intended for bump, normal, displacement or other non-color applications should select Linear sRGB as their Color Profile under the File node Attribute Editor.
• Color swatches are not color managed. To maintain a linear workflow, single color swatches in shaders, procedurals, utility nodes and lights should be converted to a linear color. A simple way to approximate this conversion is to attach a Gamma Correct node (Window > Rendering Editors > Hypershade > Maya > Utilities) to any Color attribute of a rendering node, then set the Value attribute of the Gamma node to the desired color and set all three Gamma values (RGB) to 0.455.
• Lens shaders affect the result and should be used with caution. The Physical Sun and Sky Create button in the Render Settings: Indirect Lighting tab creates a lens shader that should be deleted when using internal color management.

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