This paper deals with calibration in scientific practices which investigate relatively well-understood natural phenomena by means of already standardized instrumental
devices. Calibration is a crucial topic, since it conditions the reliability of instrumental
procedures in science. Yet although important, calibration is a relatively neglected topic.
We think more attention should be devoted to calibration. The paper attempts to take a step
in this direction. The aims are two-fold: (1) to characterize calibration in a relatively
simple kind of scientific practices; (2) to provide conceptual and taxonomic tools of
broader scope that help to get a better understanding of calibration in more complex cases
and other kinds of scientific practices. For this purpose, we first provide indications for why
a conceptual framework is needed. Second, a bibliographic survey of works dealing with
calibration is attempted. Third, we introduce different tools to enable a better understanding of calibration. Fourth, we turn to the elaboration of what we call a ‘‘simple
exemplar’’ of calibration, illustrated through the case of the calibration of an equal-arm
balance. Fifth, the tools previously introduced, and the framework of the simple exemplar,
are applied to a more complex case of calibration: calibration procedures in X-ray
experiments. This serves to show the work accomplished by the simple exemplar and to emphasize features of more complex cases of calibration. Eventually, we revisit and
specify the nature, status, scope and value of the proposed framework