After over a decade of research, ImaGem has implemented a three-factor light behavior assessment system. ImaGem’s light behavior represents a new way to quantify a diamond’s beauty as seen by the human eye. These scientifically based measures are designed to match what the human eye sees when viewing diamonds under normal lighting conditions.
ImaGem’s approach for measuring a diamond’s optical performance is determined by the three interrelated; equally important factors, namely brilliance, intensity and sparkle. By precisely measuring these, ImaGem can accurately and repeatedly define a diamond’s light handling ability.
The definitions of these terms, while technical, help to explain how each factor influences a stone’s overall beauty.
Brilliance: A measure of a stone’s overall strength of light return that represents its average light return in the face-up position. This measure is determined by computing the mean gray-scale value of all pixels within the face up view of a diamond. Brilliance is average light return.
|Very Good||120 < 150|
|Good||110 < 120|
|Fair||100 < 110|
Sparkle: A measure of those spangle-like flashes of reflected and refracted light that gives diamonds what might be called “life”. The greater the number of these flashes, the higher a stone’s sparkle. This measure is determined by measuring the standard deviation in the gray-scale value of the light return within the face-up view. Sparkle is a static predictor of potential scintillation.
|Very Good||40 < 70|
|Good||20 < 40|
|Fair||10 < 20|
Intensity: The ratio of the brightest set of pixels compared to all the pixels in the face-up view. Highly symmetric diamonds tend to have increased intensity. Intensity is a measure of contrast.
|Very Good||125 < 160|
|Good||115 < 125|
|Fair||110 < 115|