The Evaluation and Control of Direct-Reading Color Densitometers

Color densitometers are used in photographic laboratories for film processing control, printer control, print film evaluation, and negative or intermediate film evaluation. Performance characteristics of interest for a color densitometer include total and operational density range, measuring geometry, linearity, drift, noise, precision and accuracy. — The density range must be sufficient to assure satisfactory operation with specified filters. Measuring geometry and linearity are of importance to problems other than process control. Good precision implies freedom from noise and drift. Precision is of particular importance in process or printer control. Accuracy is of importance in making intercomparisons with other instruments and for film evaluation purposes. — Satisfactory routine operation of a densitometer is best obtained by means of routine operating checks, maintenance checks, and performance checks. Performance checks may be made using plaques of film or other suitable materials. The plaques may be calibrated to provide precision or accuracy performance checks. Daily checks should be plotted on control charts and may be summarized on long-range trend charts. The controls may also be combined into a single “go no-go” gauge.

Print ISSN

0898-0438

Published

1955-10

Content type

Original Research

DOI

10.5594/J14010