APCA (Accessible Perceptual Contrast Algorithm) is a new method for predicting contrast for use in emerging web standards (WCAG 3) for determining readability contrast. APCA is derived form the SAPC (S-LUV Advanced Predictive Color) which is an accessibility-oriented color appearance model designed for self-illuminated displays.

Agent skill for color science expertise. Many references covering color spaces, accessibility (APCA, WCAG), palette generation, pigment mixing, and historical color theory. Works with Claude Code, Codex, Cursor, Copilot & others.

A crate for interacting with the Alpaca API at alpaca.markets.

The APCA version, to be licensed for use with guidelines: W3/AGWG.

JS color calculator for composing colors with consistent APCA contrast ratio.

Figma plugin for displaying the contrast level and font size recommendations according to the APCA method

Figma plugin for advanced color picking, with OkLCH, APCA, WCAG and more.

A command line tool for trading stocks on Alpaca (alpaca.markets).

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𝜟𝜱✴︎ or Delta Phi Star is a variant method of determining lightness contrast, and a sibling of APCA and SACAM. It is a simplified version using easily invertible standardized maths, however it lacks some useful properties such as polarity sensitivity. In fact, it is intended for applications where a "general" simplifed perceptual contrast is desired, where polarity sensitivity is not needed (or is ambiguous).

Axe rules to check against APCA bronze and silver+ conformance levels.

A lightweight but versatile mini-lib to parse color strings, objects, or numbers, returning a simple rgba array, and related string utilities. This was developed as part of the basic APCA distro.

A TypeScript package to calculate WCAG 2.0/3.0 and APCA color contrasts

A simplified version of the APCA math to bridge from WCAG_2 contrast math to the future, while being 100% backwards compatible with WCAG_2 contrast. By "backwards compatible" we mean if bridge-pca passes it, it will automatically pass WCAG_2 contrast.

The missing introduction to APCA

A catalog of Myndex Research content, including APCA articles & documentation, related code repositories, and resources.

An accessible color scheme backed by scientific research.

Carousel with reusable cells

Send it the background color, returns black or white whichever is maximum Lc value

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Sass tools library to generate accessible colors with APCA™ contrast algorithm.

A color contrast checker that supports WCAG 2, APCA & Focus Colors

A tool to check for color contrast using APCA

what if apcaccess, but in homebridge??

apcaccess client library and cli written in node.js

Sass implementation of the Accessible Perceptual Contrast Algorithm (APCA) for the WCAG 3.0 specification.

🎨 Color contrast suggestion tool, based on APCA

Tool for Gaia DR3 astrophysical parameter re-calibration

APCA(TM) Contrast Calculator for Japanese character

Calc Game to practice differentiation for AP Calc BC exam