A screenshot attention darkroom. Blur it, drain it, shrink it, and shine an aperture across it — then look at what still shouts. Nothing you drop here leaves this browser tab.
Drag anywhere on the plate to move the aperture. Space held on Hold: original peeks at the untouched image. Arrow keys nudge the aperture; [ ] resize it.
Drag a screenshot straight onto the plate, or press ⌘V / Ctrl V anywhere on this page. Images are decoded in memory, never uploaded, and vanish when you close the tab.
Six frames on one plate: the untouched original, four single-dial passes, and your current mix with the aperture where you left it. Rendered from these canvases and saved straight to your device.
Every pass runs on offscreen <canvas> elements in this tab. Thumbnail distance downsamples to a small buffer and scales it back up with smoothing. Grayscale and contrast isolation ride the native canvas filter. Squint blur pads the plate with clamped edge pixels first so the border doesn't bleed to black. Peripheral falloff builds a second, heavier layer and masks the sharp one over it with a radial gradient centred on your aperture.
There is no server, no network request, no analytics, no storage, and no persistence of any kind. Reload the page and whatever you loaded is gone. The only thing that ever leaves is the PNG you deliberately save.