YIQ to RGB converter

It applies a fixed inverse matrix, reports both normalized and 8-bit channels, and shows when a channel had to be clipped to the displayable RGB range. Strict validation catches missing, nonnumeric, infinite, and out-of-domain inputs before calculation. The conversion is deterministic, needs no network access, and produces the same result for the same Y, I, and Q components every time.

Enter normalized YIQ components correctly

Provide three numeric components: Y for luminance, I for in-phase chrominance, and Q for quadrature chrominance. Y must be between 0 and 1, I must be between -0.5957 and 0.5957, and Q must be between -0.5226 and 0.5226. These are normalized NTSC YIQ limits, not byte values and not percentages. A Y value near zero represents low luminance, while a value near one represents high luminance. The signed I and Q components carry color information around that luminance. Enter actual JSON numbers rather than numeric strings so the contract remains unambiguous across the API, SDKs, and browser form. The converter rejects missing values, strings, NaN-like values, infinities, and numbers outside the declared component ranges. That strict behavior prevents a typing or scaling mistake from producing an apparently plausible color. Aliases such as luminance, in_phase, and quadrature are accepted for integrations that use descriptive names, but y, i, and q are the canonical fields shown in examples and documentation.

Understand the inverse NTSC matrix and clamping

The calculation uses the fixed inverse transformation R = Y + 0.956I + 0.621Q, G = Y - 0.272I - 0.647Q, and B = Y - 1.106I + 1.703Q. Each equation first produces an unclamped normalized channel. Valid YIQ components can still describe a color outside the RGB cube because the legal YIQ region is not identical to the set of red, green, and blue combinations bounded by zero and one. For that reason, each raw output is clamped independently: values below zero become zero, and values above one become one. The converter preserves the pre-clamp values in unclamped_rgb and identifies every affected channel in clipped, so clipping never happens silently. It then multiplies each clamped normalized component by 255 and rounds to the nearest integer to create familiar 8-bit red, green, and blue channels. The same integer channels are formatted as a lowercase six-digit hexadecimal color and as a CSS rgb() value. Fixed coefficients and stable decimal rounding make repeated results predictable.

Read the result and use it safely

Use red, green, and blue when an application expects separate integer channels, rgb when it expects a three-element array, hex for design tools and color pickers, or css for a stylesheet declaration. normalized_rgb is useful in graphics code that consumes channels from zero through one. unclamped_rgb is diagnostic rather than directly displayable: it reveals what the matrix produced before gamut limiting. Check clipped whenever color fidelity matters. A clipped channel means the requested YIQ point falls outside displayable normalized RGB and the returned color is the nearest result under independent channel clipping, not an exact reversible representation. This distinction is important when analyzing legacy broadcast signals, porting image-processing formulas, or comparing implementations that use different coefficient conventions. Record the chosen matrix alongside stored results if another system may use a different YIQ definition. The endpoint performs one conversion per request and costs $0.002 through the API; the pure arithmetic has no network dependency, randomness, clock access, hidden state, or locale-sensitive formatting.