Logarithmic recording spectrophotometer for densitometry and flow spectrophotometry.

A system is described for the conversion of a Beckman DU spectrophotometer to automatic recording-integrated densitometry. This system has also been applied to flow spectrophotometry with a wide-range monochromatic system substituted for the filter photometer of the Technic on AutoAnalyzer. A log converter is used which changes the impulse from linear to logarithmic and feeds this to the recorder. The converter can also be used in conjunction with the multirange control of the recorder to vary the recorded sensitivity of the spectrophotometric system; this represents a great increase in versatility to the investigator. Several applications of the instrumentation are described.