Qwen Image VAE

• Full FP32 Training of Decoder

• Works in ComfyUI

Feel free to to suggest onsite support, to civitai staff. I don't think they have any agreements like with FLUX

Overview

This model is a fine-tuned variant of the base Qwen Image VAE, modified to emphasize high-frequency detail preservation and expanded color representation, following an HDR-style reconstruction objective.

The evaluation compares the base and HDR-tuned models using perceptual, structural, distributional, and photometric metrics over identical input data.

Evaluation Summary

Perceptual Fidelity (LPIPS)

• Base: 0.0177

• HDR: 0.0786

The HDR model exhibits a significant increase in perceptual distance, indicating reduced strict identity reconstruction under deep feature similarity metrics and a shift toward detail-enhancing reconstruction behavior.

Structural Energy (Gradient Magnitude)

• Ground Truth: 404.02 (both models)

• Base Reconstruction: 313.46

• HDR Reconstruction: 687.97

The base model demonstrates strong low-pass behavior with reduced high-frequency content. In contrast, the HDR model exhibits high-frequency amplification, exceeding the structural energy of the original inputs.

Color Distribution Support

• Ground Truth: 33150.61 (both models)

• Base Reconstruction: 35004.49

• HDR Reconstruction: 40133.37

The HDR model produces a substantially expanded color support space, indicating increased chromatic dispersion and reduced quantization collapse.

Photometric Stability

Brightness Bias

• Base: 0.000351

• HDR: 0.0000098

Contrast Gain

• Base: 0.9984

• HDR: 0.99999

Both models preserve global photometric consistency, with the HDR variant showing near-perfect affine stability.

Channel Drift

• Red Shift:

  • Base: +0.0116

  • HDR: +0.0104

• Green Shift:

  • Base: -0.0606

  • HDR: -0.1856

• Blue Shift:

  • Base: +0.0187

  • HDR: +0.0219

The HDR model introduces a significantly stronger negative bias in the green channel, while maintaining comparable red and blue stability.

Interpretation

The base Qwen VAE behaves as a contractive perceptual projection operator, prioritizing smooth reconstructions and suppression of high-frequency components.

The HDR-tuned variant transitions into a detail-amplifying reconstruction operator, characterized by:

• Increased high-frequency energy

• Expanded color manifold coverage

• Higher perceptual divergence under LPIPS

• Preserved global photometric invariance

This represents a functional shift from a smoothing autoencoder regime toward a high-frequency preserving (HDR-like) reconstruction regime.