ColorBox vs Leonardo

ColorBox is a free web tool and extension for creating color systems and accessible palettes. You can adjust multiple colors in one tab and share a system as a URL or JSON file. Contrast indicators show 3:1, 4.5:1, and 7:1 levels for color sets, while HSV and OKLCH provide color-space modes. Auto Dark Mode creates an inverted set from original inputs; duplicated sets can also be edited manually. Hue progression rotates clockwise or counterclockwise. Export options include Config, Output, Tailwind, CSS, OKLCH, and Swift. The maker describes importing systems into Figma through a plugin and JSON, with custom step names and generated Paint Styles. A Sketch route uses that Figma workflow, then SVG export. The color algorithm can be consumed through NPM with exported JSON for code generation. Custom curves were described as unavailable in ColorBox at the cited time. The free plan is ad-free.

Leonardo is an open-source tool for creating, managing, and sharing accessible color systems for interface design and data visualization. Users can generate swatches from target contrast ratios or set target lightness, then adjust brightness, contrast, and saturation with adaptive themes. Sequential and diverging scales support data visualization. Accessibility tools can cycle through colorblind-safe palettes and compare color differences across color vision deficiency types, while charts and 3D models help evaluate themes. Themes and scales can be downloaded as SVG, and scales can also be exported as Tableau XML. Developer output includes parameters for @adobe/leonardo-contrast-colors, CSS custom properties, and design tokens. The related JavaScript package generates adaptive contrast-based colors and is installed with npm; its documentation includes vanilla JavaScript and React examples. The site also documents an MCP server for generating themes, checking contrast, converting colors, and creating palettes. The project is licensed under Apache V2 and has a free plan listed at free. One limitation is that generated contrast ratios can be slightly above requested values because RGB colors and color-space interpolation constrain exact results.