Color Correction Lookup Texture
Color Correction Lut (Lut stands for lookup texture) is an optimized way of performing color grading in a post effect. Instead of tweaking the individual color channels via curves as in Color Correction Curves, only a single texture is used to produce the corrected image. The lookup will be performed by using the original image color as a vector that is used to address the lookup texture.
Advantages include better performance and more professional workflow opportunities, where all color transforms can be defined in professional image manipulation software (such as Photoshop or Gimp) and thus a more precise result can be achieved.
As with the other image effects, you must have the Standard Assets Effects package installed before it becomes available.
Properties
| Property: | Function: |
|---|---|
| Based On | A 2D representation of the 3D lookup texture that will be used to generate the corrected image. |
Lookup Texture Requirements
The 2D texture representation is required to be laid out in a certain way that it represents an unwrapped volume texture (imagine an image sequence of “depth slices”).
The following image shows an example of such an unwrapped texture which effectively enhances image contrast. It should be included in the standard packages.
Texture importer requirements include enabling Read/Write support and disabling texture compression. Otherwise, unwanted image artifacts will likely occur.
Example Workflow
Always keep the basic neutral lookup texture (lut) ready as this will be the basis for generating all other corrective lut’s.
Take a screenshot of your game
Import into e.g. Photoshop and apply color adjustments (such as contrast, brightness, color levels adjustments) until a satisfying result has been reached
Perform the same steps to the neutral lut and save as a new lut
Assign new lut to the effect and hit Convert & Apply
Hardware Support
This effect requires a graphics card with pixel shaders (3.0). PC: NVIDIA cards since 2004 (GeForce 6), AMD cards since 2005 (Radeon X1300), Intel cards since 2006 (GMA X3000); Console: Xbox 360.
All image effects automatically disable themselves when they can not run on end-users graphics card.