Metamerism in color vision

The correct color display is a problem present in many industries and features. Let’s think about the world of communication, fashion, printing, etc. Specific hardware and software have been developed to try to improve and solve the problem.

In the graphic sector, wide gamut monitors, colorimeters, spectrophotometers, controlled light headsets, color management system (CMS) software, printing machines with built-in color control instrumentation have been introduced.

Over the years, moreover, a series of ISO standards have been born that dictate, among other things:

  • tolerance specific to printing ink;
  • paper-specific tolerance;
  • parameters in the various printing methodologies, such as offset and rotogravure and in extension to other systems, relating to technical aspects such as: point increase, density and spectrophotometric values of primary and secondary color filleds, etc.;
  • standards on color testing.

All this, if managed correctly and competently, is of fundamental importance in the use and control of color.

It often happens that despite all the knowledge and equipment, it is made the fundamental error of presenting a product under an uncontrolled lighting source, giving the final observer (customer) a misperception of color, due to the phenomenon of metamerism. Metamerism is the phenomenon where two visually similar colors, when observed in a different light condition, appear distinctly different from each other.

Then, there is another type of metamerism: geometric metamerism. Geometric metamerism occurs when two colors side by side equal, appear visually different by changing the angle of observation or illumination. Geometric metamerism is a physical phenomenon that in the textile sector becomes a positive aspect, as by studying appropriate textures of weaving, reflections can be obtained that give the feeling of a precious fabric. On the other hand, however, a fabric with remarkable geometric metamerism, can give many problems in photographic reproduction, especially with DSLRs.

Solutions to metamerism

To solve the problem of metamerism, it becomes important to know the color temperature of the light sources used in production environments.

Lights or highlighters are classified according to their color temperature. The color temperature is expressed in Kelvin degrees. Zero degrees Kelvin is referred to as the “absolute zero” of -273.15 °C degrees centigrade. Color temperature is also a term used in lighting technology to define the hue of light.

The control of the technical parameters of the processes and light sources used in production environments is therefore of primary importance in all industrial processes and in all applications where it is necessary to control the color, such as in the car, paint, ceramics, cosmetics, food, packaging, graphics or textile sectors. While each sector has its own control regulations, knowledge of the problem is always helpful in finding the ideal solution.

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