calibration

1) The process of comparing an instrument's output signal with reality. Instruments that measure solar energy tend to "drift", that is, their output signals do not mean the same thing from one time period to another. Because of this, they are periodically (annually or semi-annually) re-calibrated against more reliable instruments. 2) Adjusting a measuring instrument to make it accurate. The set of operations which establish, under specified conditions, the relationship between values indicated by a measuring instrument or measuring system and the corresponding values of a quantity realized by a reference standard. 3) The act of adjusting the color of one device relative to another, such as a monitor to a printer, or a scanner to a film recorder. Or, it may be the process of adjusting the color of one device to some established standard.