Stage 4.2 — background removed from the solid-key images

Approach 4.1: opaque generations on a solid key backdrop, then cut out. Under each original: algorithmic OKLab & HSV measured-key + PyMatting (local, $0) vs neural InSPyReNet / BiRefNet / RMBG-2.0 (local) and Ideogram remove-bg (API). The swatch is the key colour actually measured at the border — it drifts hot-pink / purple / even white, so we never key on the literal #FF00FF. ⚠ = self-diagnostics flagged the cell for neural escalation. Watch the filigree's hollow centre: the colour key clears it for free; neural removers tend to fill it.

Generation $0.80 · removal $0.12 · 20s gen wall · 24 cells
cutouts: OKLab key + matting 24 · HSV key + matting 24 · InSPyReNet 24 · BiRefNet HR 24 · RMBG-2.0 24 · Ideogram remove-bg 24

prompt	GPT Image 2 gpt-image-2 $0.00/image	Gemini 3.1 Flash Image google/gemini-3.1-flash-image-preview $0.07/image	MAI-Image-2.5 microsoft/mai-image-2.5 $0.00/image	Imagen 4 Fast imagen-4.0-fast-generate-001 $0.02/image	GPT Image 1.5 (magenta bg) gpt-image-1.5 $0.03/image	Ideogram 4.0 Turbo ideogram-v4 $0.03/image
general
jazz-saxophonist a jazz musician playing saxophone	62.8s · 1,059,284 B · $0.000 · solid key ↓ background removed OKLab key + matting 56% clear · 1 holes · 0.6s ⚠ HSV key + matting 56% clear · 1 holes · 0.6s ⚠ InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 1.0s RMBG-2.0 neural · local $0 · 0.5s Ideogram remove-bg neural · API · 9.3s	16.0s · 1,042,649 B · $0.067 · solid key ↓ background removed OKLab key + matting 75% clear · 2 holes · 0.3s ⚠ HSV key + matting 75% clear · 2 holes · 0.3s ⚠ InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 1.0s RMBG-2.0 neural · local $0 · 0.6s Ideogram remove-bg neural · API · 5.6s	16.4s · 938,885 B · $0.048 · solid key ↓ background removed OKLab key + matting 63% clear · 1 holes · 0.8s ⚠ HSV key + matting 63% clear · 1 holes · 0.8s ⚠ InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 1.0s RMBG-2.0 neural · local $0 · 0.5s Ideogram remove-bg neural · API · 13.4s	5.2s · 1,173,406 B · $0.020 · solid key ↓ background removed OKLab key + matting 69% clear · 2 holes · 0.7s ⚠ HSV key + matting 69% clear · 1 holes · 0.5s ⚠ InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 1.1s RMBG-2.0 neural · local $0 · 0.6s Ideogram remove-bg neural · API · 12.6s	16.5s · 1,586,755 B · $0.034 · solid key ↓ background removed OKLab key + matting 53% clear · 2 holes · 0.7s HSV key + matting 53% clear · 2 holes · 0.7s InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 1.0s RMBG-2.0 neural · local $0 · 0.5s Ideogram remove-bg neural · API · 6.3s	16.7s · 1,234,269 B · $0.030 · solid key ↓ background removed OKLab key + matting 60% clear · 2 holes · 0.8s ⚠ HSV key + matting 60% clear · 2 holes · 0.8s ⚠ InSPyReNet neural · local $0 · 1.2s BiRefNet HR neural · local $0 · 1.1s RMBG-2.0 neural · local $0 · 0.7s Ideogram remove-bg neural · API · 6.7s
birthday-cake a celebratory birthday cake with lit candles and confetti	65.4s · 1,151,761 B · $0.000 · solid key ↓ background removed OKLab key + matting 62% clear · 0 holes · 1.4s HSV key + matting 67% clear · 2 holes · 1.8s InSPyReNet neural · local $0 · 4.9s BiRefNet HR neural · local $0 · 1.6s RMBG-2.0 neural · local $0 · 0.6s Ideogram remove-bg neural · API · 5.7s	8.7s · 1,025,234 B · $0.067 · solid key ↓ background removed OKLab key + matting 87% clear · 0 holes · 0.8s HSV key + matting 87% clear · 2 holes · 0.8s InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 1.0s RMBG-2.0 neural · local $0 · 0.6s Ideogram remove-bg neural · API · 6.9s	18.1s · 854,997 B · $0.048 · solid key ↓ background removed OKLab key + matting 75% clear · 0 holes · 1.8s HSV key + matting 75% clear · 0 holes · 1.8s InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 1.0s RMBG-2.0 neural · local $0 · 0.5s Ideogram remove-bg neural · API · 15.8s	4.4s · 663,993 B · $0.020 · solid key ↓ background removed OKLab key + matting 32% clear · 3 holes · 2.9s HSV key + matting 34% clear · 3 holes · 3.1s InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 0.9s RMBG-2.0 neural · local $0 · 0.4s Ideogram remove-bg neural · API · 12.5s	15.0s · 792,385 B · $0.034 · solid key ↓ background removed OKLab key + matting 80% clear · 0 holes · 1.7s HSV key + matting 76% clear · 0 holes · 1.6s InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 0.9s RMBG-2.0 neural · local $0 · 0.4s Ideogram remove-bg neural · API · 5.5s	16.3s · 869,325 B · $0.030 · solid key ↓ background removed OKLab key + matting 69% clear · 0 holes · 1.0s HSV key + matting 69% clear · 0 holes · 1.0s InSPyReNet neural · local $0 · 1.2s BiRefNet HR neural · local $0 · 1.0s RMBG-2.0 neural · local $0 · 0.6s Ideogram remove-bg neural · API · 5.8s
design
filigree-page-border an ornate vintage filigree border framing the entire canvas edge to edge, gold double lines with corner flourishes, completely hollow center	59.7s · 1,059,155 B · $0.000 · solid key ↓ background removed OKLab key + matting 91% clear · 1 holes · 3.8s ⚠ HSV key + matting 90% clear · 6 holes · 3.4s ⚠ InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 1.0s RMBG-2.0 neural · local $0 · 0.5s Ideogram remove-bg neural · API · 9.5s	10.6s · 1,657,251 B · $0.067 · solid key ↓ background removed OKLab key + matting 66% clear · 20 holes · 18.9s ⚠ HSV key + matting 63% clear · 16 holes · 18.5s ⚠ InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 1.0s RMBG-2.0 neural · local $0 · 0.6s Ideogram remove-bg neural · API · 5.7s	16.6s · 866,427 B · $0.048 · solid key ↓ background removed OKLab key + matting 88% clear · 1 holes · 1.8s HSV key + matting 87% clear · 1 holes · 1.6s InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 1.0s RMBG-2.0 neural · local $0 · 0.6s Ideogram remove-bg neural · API · 14.4s	5.2s · 1,016,639 B · $0.020 · solid key ↓ background removed OKLab key + matting 69% clear · 10 holes · 2.8s ⚠ HSV key + matting 92% clear · 18 holes · 16.0s ⚠ InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 0.9s RMBG-2.0 neural · local $0 · 0.5s Ideogram remove-bg neural · API · 12.4s	13.1s · 479,725 B · $0.034 · solid key ↓ background removed OKLab key + matting 90% clear · 9 holes · 8.0s HSV key + matting 90% clear · 9 holes · 8.0s InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 0.8s RMBG-2.0 neural · local $0 · 0.3s Ideogram remove-bg neural · API · 5.2s	18.6s · 3,118,317 B · $0.030 · solid key ↓ background removed OKLab key + matting 48% clear · 13 holes · 19.0s ⚠ HSV key + matting 48% clear · 13 holes · 18.9s ⚠ InSPyReNet neural · local $0 · 1.3s BiRefNet HR neural · local $0 · 1.4s RMBG-2.0 neural · local $0 · 1.0s Ideogram remove-bg neural · API · 8.4s
ribbon-banner a ribbon banner scroll for a title, deep red with folded notched ends and a thin gold outline	46.1s · 882,605 B · $0.000 · solid key ↓ background removed OKLab key + matting 84% clear · 0 holes · 0.9s HSV key + matting 84% clear · 0 holes · 0.9s InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 1.0s RMBG-2.0 neural · local $0 · 0.5s Ideogram remove-bg neural · API · 7.2s	9.8s · 855,897 B · $0.067 · solid key ↓ background removed OKLab key + matting 79% clear · 0 holes · 0.3s HSV key + matting 79% clear · 0 holes · 0.3s InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 1.0s RMBG-2.0 neural · local $0 · 0.6s Ideogram remove-bg neural · API · 4.6s	14.5s · 756,256 B · $0.048 · solid key ↓ background removed OKLab key + matting 82% clear · 0 holes · 1.6s HSV key + matting 82% clear · 0 holes · 1.7s InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 1.0s RMBG-2.0 neural · local $0 · 0.5s Ideogram remove-bg neural · API · 12.0s	4.4s · 731,129 B · $0.020 · solid key ↓ background removed OKLab key + matting 83% clear · 0 holes · 0.8s HSV key + matting 83% clear · 0 holes · 0.7s InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 0.9s RMBG-2.0 neural · local $0 · 0.5s Ideogram remove-bg neural · API · 11.5s	11.8s · 383,892 B · $0.034 · solid key ↓ background removed OKLab key + matting 87% clear · 0 holes · 1.2s HSV key + matting 87% clear · 0 holes · 1.2s InSPyReNet neural · local $0 · 0.7s BiRefNet HR neural · local $0 · 0.8s RMBG-2.0 neural · local $0 · 0.3s Ideogram remove-bg neural · API · 4.6s	17.3s · 5,092,648 B · $0.030 · solid key ↓ background removed OKLab key + matting 89% clear · 0 holes · 1.5s HSV key + matting 89% clear · 0 holes · 1.6s InSPyReNet neural · local $0 · 1.2s BiRefNet HR neural · local $0 · 3.1s RMBG-2.0 neural · local $0 · 2.7s Ideogram remove-bg neural · API · 8.7s