ColorPalette Pro vs Leonardo

ColorPalette Pro is a web app for generating customizable color palettes from a base color. It creates analogous, complementary, split complementary, triadic, tetradic, and tint-and-shade palettes, with square, triangle, circle, and diamond variations for each type. Colors can be entered as text, adjusted with sliders, selected with an eyedropper, recalled from history, chosen at random, or supplied through a URL. Supported color spaces include OKLCH, LAB, LCH, HSL, and RGB. UI mode generates interface palettes with surface and on-surface colors, including light and dark versions. Palette values can be copied as CSS, saved as a CSS file, or rendered as an image; a URL can preserve the chosen color and most options for sharing. Palette images can be dragged into Figma for sampling. The app matches color names through an API using hex values and uses Color.js for color-science functions. It is open source under the MIT license, and its maker says there are no plans for ads or subscriptions. The eyedropper is unavailable in Firefox and mobile browsers.

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.