Densitometer Aperture Size vs. Density and Dot Area

During the beginning of the GATF Flexographic Project (1983-1986), a densitometer with a measuring diameter of 3.2 mm was used to measure optical density and percent dot area data. Variability in the resulting measurements was unexpectedly high. Tests indicated that measuring techniques were not at fault. Multiple measurements on a single sheet confirmed that there was a reduction of noise in the data when a densitometer with a large measuring area (4.0 mm) was used. Because of the improvement in the quality of the data, the large spot densitometer was used for density measurements and dot area calculations throughout the project.