Densitometer calibration

Densitometers evaluate color through the CMYK system. These devices are widely used in the graphics industry and printing services.

The operation of this device is similar to a Colorimeter used to measure color coordinates. In particular, a densitometer measures the result of the interaction of radiation (light/source) found by a Detector (observer) with an object. Reflection densitometers evaluate the light reflected from a sample, substrate, or paper under test.

Therefore, to measure optical density, it is necessary to know the measurement geometry (incident angle and reflection of light), the type of light (source) and the observer.

geometry

The densitometer illuminates the sample from an angle of 45º and measures the light reflected at 0º.

light source

A light source is the type of light that falls on the sample whose color you want to measure. It is the spectral distribution curve of the light source. In the graphic arts, it's common to work in D50 and D65.

observer

To detect and measure color, an observer is always required. The CIE standardized the different types of observers, so each represents a different field of view. Specifically, CIE stands for 2º and 10º observers.

Density Meter Response

The reading conditions for optical density measurements are specified in different regulations. The density meter can measure under the following conditions:

State A: ANSI PH2.18, Density Meter Response. This standard applies to reflection densitometers used in color photogrammetry. It defines response functions for measuring photographic products such as photographic prints, 35mm slides, and transparency.

State E: Densitometer Response, the European recognized standard for colored reflection densitometers. It defines the response function of a broadband densitometer commonly found in European graphic arts companies.

State I: Densitometers are called narrowband. It defines the response function for narrowband densitometers used in North America.

State T: broadband color reflectance densitometer response. It is the accepted standard for this type of density meter in the United States. Defines response functions for measuring press proofs, photomechanical proofs and press sheets, and for measuring other graphic art materials measured by broadband equipment. Response of a densitometer used by Graphic Arts North America.

In addition to densitometric measurements, the Spectrophotometer also measures CIELab* color coordinates.

Technical scope of density meter calibration