# Stability A/B report: NERVE vs SPAN_S

**Setup.** Both networks were trained from scratch with **identical configs** - only
`network_g` differs (NERVE vs SPAN_S). Same data, same degradation, same losses,
same schedule. Everything is in `configs/`.

**Validation.** Urban100 OTF x4 (degraded on the fly with the training pipeline). PSNR/SSIM at each validation step.\n\n## Graphs

- `losses.png` - training losses (charbonnier, MS-SSIM, perceptual) for both networks.
- `validation.png` - validation **PSNR** (left) and **SSIM** (right).
- `colour_stability.png` - the average per-channel colour difference between the model
  output and the ground truth, in 0-255 units, at each checkpoint. One panel per colour
  channel plus a combined "largest bias" panel. **Flat lines near 0 mean the model is not
  developing a colour cast while it trains**; big swings or a rising trend mean it is.

Raw numbers: `colour_bias.csv`.