Color Instruments Metrology

• Repeatability
Repeatability is how well an instrument can repeat identical measurements.
Repeatability can be quantified in terms of short, medium, and long times between
measurements. These types of repeatability are taken over seconds or minutes (short); hours (medium); and days, weeks, or longer (long). Intuitively, repeatability can be thought of as the degree to which an instrument makes self-consistent measurements.

• Reproducibility
Reproducibility is similar to repeatability except that some aspect of the
measurement conditions have changed. This might be the operator, the instrument, or some
other condition. The intuitive understanding of reproducibility is the degree to which an
instrument makes consistent measurements even when conditions are slightly changed.

• Inter-instrument and Inter-model Reproducibility
These are special cases of repeatability where instruments of identical design (inter-instrument) or different design (inter-model) are compared.

• Accuracy
Accuracy is how closely an instrument can conform to the accepted value for a given sample. “Accepted” values are usually provided by a high-accuracy laboratory, such as a national standards body. From these samples, accuracy is independently determined for the wavelength scale and the radiometric scale.

http://www.color.org/ICC_white_paper_22_Precision_and_Bias_in_Measurement.pdf