Updated on 3rd May 2021

Colorimeters and spectrophotometers are the two types of colorimetric measuring instruments used to capture, analyse, and communicate color. In the dental industry, it is needless to say that color accuracy (tooth shade) is important and it is clear that making a reliable colorimetric measurement is essential for the manufacture of a quality dental prosthesis.

However, there is confusion today among many users and healthcare professionals, arising from the lack of information provided by manufacturers. This is why we are going to answer your questions related to these two devices using two very distinct technologies: spectrophotometry and colorimetry.

  • Colorimeter

It is a trichromatic colorimetric measurement tool that provides an objective assessment of color characteristics from light passing through the primary filters of red, green and blue. It simulates the way the human eye perceives color.

How does a colorimeter work?

The tooth is illuminated at an angle of 45 ° by an internal light source.

The light passes through the trichromatic filters, which indicate the amount of red, green and blue light reflected by the tooth.

The filter’s measurements are quantified in RGB values, which simulate the sensitivity of human eyes to light.

  • Spectrophotometer

A spectrophotometer is a more complex colorimetric measuring instrument that takes into account light intensity as a parameter of color. It performs full-spectrum colorimetric measurement, as opposed to the trichromatic procedure of a colorimeter, and generates colorimetric data that is beyond observation by the human eye.

 How does a spectrophotometer work?

An internal light source (On the Rayplicker, this source is represented by the ring of LEDs at the end of the measuring head) emits under different wavelengths so as to represent the entire visible color spectrum.

Each Led representing a specific wavelength of the spectrum emits one after the other in order to diffuse the light on the tooth.

Under each emission wavelength, the sensor measures the light intensity and absorbance of the tooth being analysed.

These collected data are then analysed by a comparison algorithm which compares the information collected with the spectral signatures of the various previously recorded shade guides.

The spectrophotometer displays this information in digital form.