{
  "test_date": "2026-10-19",
  "kind": "controlled synthetic test, NOT native Gemini watermarked downloads",
  "scene_seed": 20261019,
  "engine_sha256": "d956d58d3f5b195990c17549893eaf773bac4de7dba5ed4d61495f0c0f919e78",
  "alpha_map_sha256": "69fc428ed9cdf7769ca63d2d70c2b5d661acbc88adf3ff1632f882a63c0f98ed",
  "encoder": "Pillow 12.3.0; JPEG chroma subsampling=2; PNG compression=6; not browser encoding",
  "formula": "box_rgb_mae_vs_ground_truth = sum(abs(cleaned_RGB - known_original_RGB)) / (48 * 48 * 3); maximum is max of these absolute channel differences. Same-encoding-control MAE replaces known_original_RGB with decoded unmarked control encoded with identical settings. Outside count compares cleaned RGBA with decoded marked input, counting pixels with any channel changed, excluding the edit box.",
  "results": [
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      "width": 1024,
      "height": 768,
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      "box_max_channel_error_vs_ground_truth": 14,
      "box_rgb_mae_vs_same_encoding_unmarked_control": 0.8339120370370371,
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      "box_max_channel_error_vs_ground_truth": 25,
      "box_rgb_mae_vs_same_encoding_unmarked_control": 1.806568287037037,
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      "strength": 1.0,
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      "box_max_channel_error_vs_ground_truth": 34,
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      "box_max_channel_error_vs_ground_truth": 41,
      "box_rgb_mae_vs_same_encoding_unmarked_control": 4.228732638888889,
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    }
  ]
}