Color input and conversion
PIQE color tools accept opaque three- or six-digit HEX values and normalize them to six uppercase digits. HEX is interpreted in sRGB. RGB channels use the 0–255 range; HSL is derived from the sRGB channel extrema; CMYK is shown only as an unprofiled mathematical approximation.
OKLCH output is computed by linearizing sRGB, transforming through Oklab, and converting the a/b axes to chroma and hue. Display values are rounded for readability, while calculations retain greater precision. Round-trip conversion can differ by a small amount after display rounding.
Contrast calculation and tests
Relative luminance follows the WCAG sRGB formula: channels are linearized, combined with the standard luminance coefficients, and compared using (lighter + 0.05) / (darker + 0.05). The code is tested against 21:1 for black on white, 1:1 for identical colors, and the known borderline behavior of #777777 on white.
The result rows use WCAG 2.2 thresholds for normal text, large text, and meaningful UI graphics. The tool does not round a failing ratio into a pass. Transparent colors, gradients, images, antialiasing, and display conditions require the final rendered result.
Palette generation and mixing
Generated palettes start from a hue relationship—balanced, analogous, complementary, triadic, warm, or cool—then deliberately vary lightness and chroma so the five candidates can occupy different roles. Locked swatches are preserved. Generation offers candidates and never claims accessibility until a particular pair is tested.
The mixer uses a weighted interpolation of opaque sRGB channel values. This is reproducible digital blending, not pigment or spectral mixing. A final production ramp may need perceptual tuning in OKLCH.
On-device image color extraction
The browser resizes large images in memory to control work, reads opaque pixels through the Canvas API, groups nearby sRGB values into quantized buckets, ranks the buckets by frequency, and removes candidates that are too close in perceptual distance. Up to six distinct colors remain.
The file is not uploaded. Dominance is mainly area, not semantic importance. Users can click a precise pixel when a small but important accent is absent. Transparent pixels are ignored; compression, profiles, antialiasing, and display color management affect the values.
Public-domain art palette process
PIQE first verifies the museum record, accession, image source, and Public Domain or Open Access statement. Launch sources are the Metropolitan Museum of Art, the Art Institute of Chicago, and the Rijksmuseum. Local copies are kept to reduce external tracking and broken-image risk, while every page links back to the museum record and rights statement.
A reproducible script samples the reproduction and lists frequent color buckets. Editorial review then removes near-duplicates, compares the broad value and temperature structure, and preserves small accents when they are compositionally important. Five sRGB HEX values are assigned descriptive names and practical roles. They are interpretations of a digital reproduction, not measurements of original pigments.
Each artwork page contains at least three distinct visual observations, two design applications, calculated contrast pairs, extraction notes, and source links. We do not use works with unclear rights, and the initial advertising-safe collection excludes nudity, graphic violence, and other high-risk imagery.
Source, localization, and update review
Technical claims prefer standards bodies, official documentation, original authors, and museum collection records. Page copy is written for a specific decision rather than assembled by changing a keyword. English and Korean pages are independently reviewed for meaning; they are not exposed as untranslated keys or machine-only fragments.
Every launch page carries a real review date of September 2, 2026. A page is updated when a referenced standard changes, a bug affects output, a rights record changes, or a correction materially improves the decision. Cosmetic date changes without content review are not allowed.