Printmaking · browser-local two-ink dithering · 2026 · Solo — product framing, test-first raster logic, interaction design, accessibility, responsive verification, production deployment
Raster Proof
A two-ink image bench that makes the conversion from continuous tone to printable pixels visible, inspectable, and portable.
The problem
Indie game artists, zine makers, and hands-on printmakers often need to reduce an image to two visible colors, but a generic image editor leaves the relationship between threshold, dot method, source tone, and final pixel pattern scattered across separate dialogs. Raster Proof keeps that narrow conversion causal: open one local image or use the controlled study, compare threshold, ordered 4×4, and Floyd–Steinberg output beneath a draggable wipe, point at any pixel to read its source luma and binary decision, then copy the exact recipe or download a nearest-neighbor PNG. It is a deterministic screen preview rather than a press simulation; dot gain, trapping, registration, substrate absorption, ink opacity, physical screen frequency, and final output scale remain outside its model and require a physical proof. Images are sampled into ephemeral browser memory and never uploaded. There is no account, persistence, paid API, tracking SDK, outbound email, advertising, payment, or destructive operation. Production deployment dpl_GMFWtH1K4efnmzfBbecXU84FFSGJ reached READY before independent Foundry artifact, HTTPS deploy, and six-step behavior checks passed at the stable alias.
Architecture
Key decisions
Make the conversion boundary the instrument
The vertical wipe is not a decorative before-and-after. It clips the actual dithered canvas over the sampled tonal canvas, while the pointer inspector reads the same source and binary output at one coordinate.
Offer three explainable algorithms
Hard thresholding exposes the cutoff, the 4×4 Bayer matrix produces a stable ordered grid, and Floyd–Steinberg carries quantization error to neighboring pixels. Each path is deterministic and covered by a focused pure-logic test.
Keep print claims narrow
Raster Proof exports pixels and a recipe only. It explicitly avoids claims about physical dot gain, trapping, registration, stock, opacity, or production suitability and asks for a proof at final size.
Use an original prepress inspection bench
Ruled stock, bottle-green inspection space, vermilion controls, acid focus and wipe marks, Georgia hierarchy, condensed operating copy, and monospaced evidence produce a dense Command / Inspect surface without gradients, blur, feature tiles, icon toppers, center stacking, or ornamental metrics.
Let release failures strengthen the gate
A current framework audit exposed critical inherited advisories and the upgraded ESLint package invalidated the legacy compatibility wrapper. Patched dependencies, a native flat config, and a clean rebuild restored zero production vulnerabilities without bypassing tests or checks.