calibrated

Calibrated is the adjective used to describe an instrument, measurement system, or process that has been adjusted and tested against known standards to produce accurate and consistent results. In metrology, calibration is the process used to determine and correct systematic errors, enabling measurements to be traceable to international or national standards such as the SI units. An item described as calibrated implies that its measurement readings are valid within stated uncertainty bounds for specified conditions.

Calibration involves comparing the instrument's output with reference values provided by a standard, determining any bias, scale factor, or nonlinearity, and applying adjustments or corrections. The steps typically include selecting a reference standard, performing measurements across a defined range, computing correction factors, implementing adjustments, and validating the result with independent checks. Calibration data yields a calibration certificate that records the instrument, method, uncertainties, and traceability.

Calibrated devices appear in many domains: laboratory instruments (thermometers, balances, spectrophotometers), industrial sensors and process controllers, medical devices, household thermometers, and display systems. In photography and display technologies, monitor or color-calibrated devices are adjusted to render colors consistently.

Calibration is distinct from validation, which assesses whether a system meets its intended use, and from adjustment, which modifies the device directly. Calibration may be periodic or continuous, and the associated uncertainty depends on the method, standards, and environmental factors. Traceability chains ensure measurements can be linked to SI units through documented calibration history.

See also: metrology, calibration, traceability, uncertainty, standardization.