ABSTRACT
Densitometry is most widely applied in photographic science, and measurements in this field are covered by a four-part ANSI/ISO standard. The measured density of a given sample can be affected significantly both by the design of the equipment and the nature of the sample. Therefore, the first rule of practical densitometry is that the sample must be measured in a way that is meaningful with respect to its intended use. By the first law of densitometry, however, any sample should be measured with a system whose spectral response is equal to that used in actual practice—in other words, color negative samples should be measured with the Status M filters. However, the analysis works satisfactorily with the status filters, which are relatively narrowband, and much practical densitometry is performed in this manner. Densitometry is an example of the basic mechanism by which the instrument operates—comparing the flux reaching the sensor with and without the sample in place.
