Qwen Image 2.1's alpha channel is noisy, not empty — fix released as ComfyUI node
Riot_Revenger · reddit · 2026-09-26
Testing community claims about Qwen Image 2.1's alpha channel, the author found it isn't empty but consistently noisy: visualizing alpha values 0-255 as a color map shows values scattered across the range, with the model struggling to output absolute 0 (fully transparent) or 255 (opaque) — likely inherent to diffusion.
The author built a ComfyUI custom node, ComfyUI-Clean-Alpha, with AI assistance: it clamps per-pixel alpha to 0 or 255 past thresholds and drops the alpha channel entirely when all values are 255. Prompts used for transparent-background generation are included in the post.
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