The D50 daylight myth

Does 5000K really equal daylight? Fiction. GTI is here to debunk some daylight myths for you. In short, 5000K does NOT equal daylight. Now that that’s cleared up… 5000 Kelvins (5000K)

Complete guide to lamp performance

GTI Graphic Technology Inc. Graphiclite® and ColorMatch Series® lamps are in a class all their own when it comes to fulfilling the demands of industry standards, but knowing the proper


Metamerism exists when two materials match under some lighting conditions but not under other lighting conditions. It is the occurrence of colors which have different properties appearing to match under a

What is ISO 3664:2009?

A summary of the graphic arts and photography standards. ISO 3664 is the international color viewing standard for the graphic technology and photography industries. In order to improve the quality

Color Rendering Index (CRI)

Color viewing, even near the D50 standard color temperature, is only as accurate as the quality of the light source. The CRI, or color rendering index, is a quantitative scale

Spectral power distribution (SPD)

A spectral power distribution (SPD) is a graph of the energy levels of a light source through a range of wavelengths of light. The spectral power distribution is the true “fingerprint”

Color temperature

Color temperature is the expression of energy levels of light sources in Kelvins (K), based on the notion of a perfect absorber which changes color dependent on the temperature it


Iso 3664 defines Chromaticity as the “property of a color stimulus defined by its chromaticity coordinates, or by its dominant or complementary wavelength and purity taken together.” The apparent color of

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