Blend up to 12 colors into one. Each color may be a hex (#d2bc93), a CSS name (red), an RNV brand name (brand gold, near-black), or a saved-palette reference (Spring line, or 'Spring line:2' for its 2nd swatch). Optional integer weights bias the blend (defaults to equal). mode selects the model: rgb/hsv/lab are digital blends (lab is perceptual and the default); paint mixes pigments via Kubelka-Munk physics (colors darken like real paint); ryb is the artist's color wheel; cmy is subtractive like printer inks. Returns hex and rgb.

Convert a color between formats. Input accepts a hex, CSS name, RNV brand name, or saved-palette reference. With to set to one of hex/rgb/hsv/hsl/lab, returns just that format; otherwise returns all of them.

Generate a color harmony from a base color. base accepts a hex, CSS name, RNV brand name, or saved-palette reference (e.g. 'Spring line:2'). scheme is one of: complementary, analogous, triadic, split-complementary, tetradic (a.k.a. square), monochromatic, compound. Returns a list of hex colors.

Perceptual difference (Delta-E) between two colors. color1 and color2 accept a hex, CSS name, RNV brand name, or saved-palette reference. method is 'ciede2000' (default, modern standard) or 'cie76'. A value near 1.0 is the threshold the eye can just notice; larger means more different. Returns the value and a plain-language interpretation.

WCAG contrast ratio between a foreground and background color, for accessibility. Both accept a hex, CSS name, RNV brand name, or saved-palette reference. Returns the ratio (1.0-21.0) plus pass/fail for AA and AAA at normal and large text sizes and for UI components. Use this to check if text will be readable on a background.

Apply an exact, deterministic text transformation. operation is one of: UPPERCASE, lowercase, 'Title Case', 'Sentence case', camelCase, PascalCase, snake_case, CONSTANT_CASE, kebab-case, dot.case, 'iNVERTED cASE'. Use this rather than converting case by hand.

Save (or update) a named palette for later reuse, e.g. a launch line. colors is a list of hex values; optional notes are stored as the palette's description. Author is recorded as RNVizion.

List every saved palette as name + colors.

Retrieve one saved palette by name, returning its colors and metadata. Returns null if no palette by that name exists.