dark HDR · domain only
Toys: sRGB L2 − amplitude L2
+0.149JOD
+0.91 dBPSNR
+0.0219SSIM
Primary comparison
Domain-only effect
Each card is sRGB-domain loss minus the same formula in amplitude. Positive JOD/PSNR/SSIM is better.
bright HDR · domain only
Castle: sRGB L2 − amplitude L2
+0.068JOD
+0.16 dBPSNR
-0.0026SSIM
dark HDR · domain only
Toys: sRGB Charb − amplitude Charb
-0.021JOD
-0.17 dBPSNR
-0.0100SSIM
bright HDR · domain only
Castle: sRGB Charb − amplitude Charb
+0.029JOD
+0.06 dBPSNR
-0.0001SSIM
Formula-only comparison
Robust residual effect
Amplitude Charbonnier minus amplitude L2 keeps the domain fixed and changes only the penalty shape.
dark HDR · formula only
Toys: amplitude Charb − amplitude L2
+0.120JOD
+3.86 dBPSNR
+0.1154SSIM
bright HDR · formula only
Castle: amplitude Charb − amplitude L2
+0.248JOD
+1.96 dBPSNR
+0.0970SSIM
Result: sRGB conversion helps L2 substantially on dark Toys, but barely helps bright Castle. It does not improve Charbonnier in Toys and is nearly neutral in Castle. In these two matched runs, the larger and more consistent gain comes from the Charbonnier penalty itself—not from converting residuals to sRGB.
dark HDR · median 1.9 nits
Toys
Ground truth
Per-image q99.9-normalized HDR target
Amplitude L2
JOD 9.083 · PSNR 28.08 dB · SSIM 0.6451 · L2 0.001555
sRGB L2
JOD 9.232 · PSNR 28.99 dB · SSIM 0.6670 · L2 0.001262
Amplitude Charbonnier
JOD 9.203 · PSNR 31.94 dB · SSIM 0.7605 · L2 0.000640
sRGB Charbonnier
JOD 9.182 · PSNR 31.77 dB · SSIM 0.7505 · L2 0.000665
| Loss at 300 | JOD ↑ | PSNR ↑ | SSIM ↑ | sRGB L2 ↓ |
|---|---|---|---|---|
| Amplitude L2 | 9.083 | 28.08 | 0.6451 | 0.001555 |
| sRGB L2 | 9.232 | 28.99 | 0.6670 | 0.001262 |
| Amplitude Charbonnier | 9.203 | 31.94 | 0.7605 | 0.000640 |
| sRGB Charbonnier | 9.182 | 31.77 | 0.7505 | 0.000665 |
bright HDR · median 184.6 nits
Castle
Ground truth
Per-image q99.9-normalized HDR target
Amplitude L2
JOD 8.772 · PSNR 24.71 dB · SSIM 0.6018 · L2 0.003378
sRGB L2
JOD 8.840 · PSNR 24.87 dB · SSIM 0.5992 · L2 0.003256
Amplitude Charbonnier
JOD 9.020 · PSNR 26.67 dB · SSIM 0.6988 · L2 0.002154
sRGB Charbonnier
JOD 9.049 · PSNR 26.73 dB · SSIM 0.6987 · L2 0.002124
| Loss at 300 | JOD ↑ | PSNR ↑ | SSIM ↑ | sRGB L2 ↓ |
|---|---|---|---|---|
| Amplitude L2 | 8.772 | 24.71 | 0.6018 | 0.003378 |
| sRGB L2 | 8.840 | 24.87 | 0.5992 | 0.003256 |
| Amplitude Charbonnier | 9.020 | 26.67 | 0.6988 | 0.002154 |
| sRGB Charbonnier | 9.049 | 26.73 | 0.6987 | 0.002124 |
