Array spectroradiometers are used pervasively in light measurement. However, their properties are not widely understood by users. CIE 233:2019 seeks to educate users in the characteristics of array spectroradiometers that are important to obtaining accurate measurement results. Moreover, performance indices are proposed that will enable users to rank instruments according to the properties that affect their applications. In many cases, if the array spectroradiometer is properly characterized, correction can be made to measurements that will improve the accuracy. Details of the nature and use of these corrections are given. Calibration procedures and uncertainties are discussed for various common quantities, giving a sound foundation to measurements. Background information, underlying the discussions, is found in the annexes and references.