Gemprint Light Performance

Light Return

Light Return is also known as brilliance or total brightness.  It’s the exceptional way diamonds reflect and refract light creating a luminous return of light to a viewer’s eye that has made diamonds sought after for centuries.  Gemprint’s Light Performance technology captures and measures the actual output of light from a diamond.  The Gemprint instrument shines a single beam of light (a red laser) into a diamond and analyzes the light coming back out of the diamond. First, data is captured by directing the light beam directly perpendicularly into the diamond, and then the instrument directs the light beam at the diamond while it is tilted approximately 12-14 degrees in eight different directions to establish the light return from different angles. The data is complied, analyzed, and graded on a scale of Fair, Good, Very Good, and Excellent.

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Critical Angle

For more than one hundred years, mathematicians and diamond cutters have understood the important role that the critical angle of diamond plays in creating a brilliant, well cut diamond.  The critical angle (incident pavilion angles) determines if light entering through the crown (top) is reflected back through the crown or leaked out through the pavilion (bottom).  You can see in the images of shallow and deep cut diamonds, how Gemprint’s direct assessment of light return correlates to well documented cutting standards.

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Optical Symmetry

Optical Symmetry is the evenness of light return.  It is determined by the equality of every facet and angle, the alignment of the crown and pavilion, and the orientation of the table and culet. Basically, it is an assessment of a diamond cutter’s craftsmanship, attention to detail, and overall skill. 

The Optical Symmetry image is the light return captured when the diamond is perpendicular to the light beam (the Gemprint).  The equality of the light return is computed mathematically and analyzed on a scale of Fair, Good, Very Good and Excellent.  To promote easy visualization of the symmetry, the image is colorized and divided into eight equal parts; the more even the pattern in each section, the better the Optical Symmetry.

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Scintillation

For more than one hundred years, mathematicians and diamond cutters have understood the important role that the critical angle of diamond plays in creating a brilliant, well cut diamond.  The critical angle (incident pavilion angles) determines if light entering through the crown (top) is reflected back through the crown or leaked out through the pavilion (bottom).  You can see in the images of shallow and deep cut diamonds, how Gemprint’s direct assessment of light return correlates to well documented cutting standards.

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