The current halation and grain modules are artifacts from an early alpha release and there are several issues with them:

1. Halation and grain do not belong in the Luminance panel.
2. The modules are not turned off by hold-clicking on the image (before/after) or split screen view
3. Grain uses simplistic texture blending implementation.

What to expect from the update:

Grain will be replaced with a Film Structure module that combines new and advanced film acutance, softness and grain in a single structure emulation tool for incredibly realistic emulsion properties.

Halation color will be simulated through color space transform instead of a texture-location dependent effect. This ensures that all non-structural properties of the halation module carry over into 3D LUT exports for greater highlight color consistency between color.io and third party editing/grading apps.

These modules will be located somewhere else in the UI under a "Film Material" category with individual presets that emulate real world film stocks from Kodak, Fuji and Agfa.