Understanding Color Management with EffectComposer in Three.js

I understand your confusion regarding color management, output colorspace, and post-processing in Three.js. While I can provide some general guidance based on the available documentation, it appears that your specific questions touch on some nuanced interactions that may require deeper investigation.

Post-Processing with EffectComposer

The EffectComposer is a utility in Three.js that allows you to apply multiple post-processing effects in sequence. It's mentioned in the documentation as an important addon for handling post-processing effects.

Regarding your specific questions:

1. OutputPass Functionality

The OutputPass is designed to handle the final color space conversion in a post-processing chain. Based on your observations, there seems to be some inconsistency in its behavior:

• When using LinearSRGBColorSpace, the OutputPass should convert to sRGB for display, but you're not seeing this happen
• With SRGBColorSpace, the conversion appears to happen automatically without the OutputPass

This suggests there might be some overlap or redundancy in how the color conversion is being applied.

2. Correct Configuration

The documentation indicates that when using post-processing, setting the renderer's output colorspace to SRGBColorSpace is optional. This implies that:

• Without post-processing: Set renderer.outputColorSpace = THREE.SRGBColorSpace for proper display
• With post-processing: Either handle the conversion in the renderer OR in the post-processing chain (via OutputPass)

Potential Issues

Based on your description, there could be several explanations:

1. The OutputPass might not be correctly configured or might be redundant when the renderer is already set to SRGBColorSpace
2. There might be changes in recent Three.js versions that aren't fully reflected in all documentation
3. The interaction between renderer settings and post-processing might be more complex than documented

Recommendation

Since the documentation you've referenced seems to be giving mixed signals, and your practical tests show inconsistencies, I would recommend:

1. Try setting renderer.outputColorSpace = THREE.LinearSRGBColorSpace when using EffectComposer with OutputPass as the final pass
2. Check if your Three.js version matches the documentation you're referencing
3. Consider posting your specific issue to the Three.js forum or GitHub issues for more targeted assistance

The documentation suggests that post-processing should work with proper color management, but the specifics of implementation might require some experimentation or further clarification from the Three.js maintainers.