Light Behavior
Locked inside every diamond is the secret to its unique beauty. ImaGem light behavior analysis looks into the soul of an individual diamond and provides direct numeric measures of brilliance, sparkle and intensity that correlate with what the human eye can see.
Importance of Cut and Appearance in Light behavior
The most important aspect of a diamond that any person can see is its appearance. The appearance of a stone depends on the size, shape, cut and its light behavior. For centuries, improvements in cut have been made to bring out the best light behavior in a diamond. Until recently direct measurement of light behavior in diamonds was not perfected and proportions were used as a substitute to predict its light behavior.
New technology has been developed to measure light behavior in a diamond. Two approaches have emerged – one approach is to predict light behavior in a diamond using a model and the other is to directly measure the light behavior using the actual diamond.
The first approach relies on measuring the proportions of a diamond and then using a model to predict how a diamond will perform. There are several problems with this approach. First is – most of the research has been done for round diamonds and light behavior of many other shapes cannot be predicted. Second is the modeling approach does not take into consideration a diamond’s color, flaws, fluorescence and other nuances which are known to affect light behavior. Many experts therefore believe that while modeling approach maybe useful in the cutting process, it is not the right approach to determine the actual light behavior of a cut and polished diamond.
The second approach directly measures the light behavior of a finished, cut and polished diamond. This approach has many benefits. First is, direct measurement of light behavior can be used for any shapes and branded cuts right now. Second is, color, clarity, faceting and other nuances of a diamond are taken into account while measuring the light behavior of a diamond directly.
ImaGem is a pioneer in direct measurement of light behavior in diamonds and other gem stones. It holds 3 international patents and scores of claims related to direct measurement of light behavior. The technology allows the measurement to be taken in less than 30 seconds. It also allows to rotate a diamond to see scintillation and fire in a diamond. This technology has been tested over many years and has proven that diamonds that have high performance on ImaGem’s direct measurement scale will have high scores on appearance from consumers and experts. ImaGem and many experts believe that light behavior will become a standard on all grading reports in the near future.
ImaGem’s direct measurement of light behavior is the perfect way for sellers and buyers to See the Light and Know a Diamond with confidence.
Light Behavior Trinity Revealed
<div style="display: block;" id="bobcontent3" class="switchgroup1"> <span style="font-style: italic;"> <span style="font-weight: 400;"><font ;="" face="verdana" size="3">Technical Definitions and descriptions of ImaGem's direct measures of Light Behavior</font></span> </span> <p></p> <p><font ;="" face="verdana" size="2"> 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. </font></p> <p><font ;="" face="verdana" size="2">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. </font></p> <p><font ;="" face="verdana" size="2">The definitions of these terms, while technical, help to explain how each factor influences a stone’s overall beauty. </font></p> <p align="left"><span style=""><font ;="" face="verdana" size="2">Brilliance:</font></span><font ;="" face="verdana" size="2"> 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.</font></p>
<div align="left"> <font ;="" face="verdana" size="2"> <table id="table1" border="1" width="35%"> <tbody><tr> <td align="center"><p align="center">Excellent</p></td> <td align="center"><u> <span style="position: relative; top: -1pt;">></span></u> 150</td> </tr> <tr>
<td align="center"><p align="center">Very Good</p></td> <td align="center">120 < 150</td> </tr> <tr> <td align="center"><p align="center">Good</p></td> <td align="center">110 < 120</td>
</tr> <tr> <td align="center"><p align="center">Fair</p></td> <td align="center">100 < 110</td> </tr> <tr> <td align="center"><p align="center">Poor</p></td>
<td align="center">< 100</td> </tr> </tbody></table> </font></div> <div align="center"> <font ;="" face="verdana" size="2"> </font><p align="left"><font ;="" face="verdana" size="2"><b>Sparkle:</b> 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. </font></p>
<font ;="" face="verdana" size="2"> </font><div align="left"> <font ;="" face="verdana" size="2"> <table id="table2" border="1" width="35%"> <tbody><tr> <td align="center" width="165"><p align="center">Excellent</p></td> <td align="center"><u> <span style="position: relative; top: -1pt;">></span></u> 70</td> </tr> <tr>
<td align="center" width="165"><p align="center">Very Good</p></td> <td align="center">40 < 70</td> </tr> <tr> <td align="center" width="165"><p align="center">Good</p></td> <td align="center">20 < 40</td>
</tr> <tr> <td align="center" width="165"><p align="center">Fair</p></td> <td align="center">10 < 20</td> </tr> <tr> <td align="center" width="165"><p align="center">Poor</p></td>
<td align="center">< 10</td> </tr> </tbody></table> </font></div> <font ;="" face="verdana" size="2"> </font><div align="center"> <font ;="" face="verdana" size="2"> </font><p align="left"><font ;="" face="verdana" size="2"><b>Intensity:</b> 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.</font></p>
<font ;="" face="verdana" size="2"> </font><div align="left"> <font ;="" face="verdana" size="2"> <table id="table3" border="1" width="35%"> <tbody><tr> <td align="center" width="165"><p align="center">Excellent</p></td> <td align="center"><u> <span style="position: relative; top: -1pt;">></span></u> 160</td> </tr> <tr>
<td align="center" width="165"><p align="center">Very Good</p></td> <td align="center">125 < 160</td> </tr> <tr> <td align="center" width="165"><p align="center">Good</p></td> <td align="center">115 < 125</td>
</tr> <tr> <td align="center" width="165"><p align="center">Fair</p></td> <td align="center">110 < 115</td> </tr> <tr> <td align="center" width="165"><p align="center">Poor</p></td>
<td align="center">< 110</td> </tr> </tbody></table> </font></div> <font ;="" face="verdana" size="2"> </font></div> </div> </div>
Technical Definitions and descriptions of ImaGem’s direct measures of Light Behavior
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.
| Excellent | > 150 |
| Very Good | 120 < 150 |
| Good | 110 < 120 |
| Fair | 100 < 110 |
| Poor | < 100 |
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.
| Excellent | > 70 |
| Very Good | 40 < 70 |
| Good | 20 < 40 |
| Fair | 10 < 20 |
| Poor | < 10 |
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.
| Excellent | > 160 |
| Very Good | 125 < 160 |
| Good | 115 < 125 |
| Fair | 110 < 115 |
| Poor | < 110 |
Scintillation and Fire
Scintillation in a diamond represents flashes of light when a diamond is moved. Because of the dynamic nature, it is difficult to measure this property in a diamond. Likewise, fire in a diamond; break up of light into a spectra, depends on movement of either a diamond or a light or a viewer. This property is also difficult to measure.
ImaGem is the only technology currently available that offers cutters and polishers, gemologists, wholesalers, retailers and consumers to directly view the dynamic properties of scintillation and fire.
This is accomplished by rotating a diamond under normal lighting conditions and continuously viewing the beautiful display of flashes of light and fire present in a diamond. This approach is a powerful sales tool available only through ImaGem.
Experience the dynamic aspects of Scintillation and Fire in the videos shown below.
Comparison of Diamonds using Direct Measurement of Light Behavior
Poor |
Fair |
Good |
Very Good |
Excellent |
|
| Brilliance |  <100 |
 100 – 110 |
 110 – 120 |
 120 – 150 |
 150 – 205 |
| Sparkle |  <10 |
 10 – 20 |
 20 – 40 |
 40 – 70 |
 70 – 120 |
| Intensity |
|
 110 – 115 |
 115 – 125 |
 125 – 160 |
 160 – 430 |
