VIRTUAL DIAMOND POLISHING: PRINCIPLES AND ADVANTAGES
The traditional ways of processing diamonds are hundreds of years old, and are based on previous experience and knowledge of the optimal polishing angles for each model of polished diamond. As computer technologies and 3D simulation software developed, it was only a matter of time until the diamond industry adopts innovate methods for rough and polished diamond planning.
Today, cutters and polishers often plan rough or polished diamonds using automated optimization software. Virtual polishing takes the planning process for all diamonds one step forward to ensure a plan that will yield the best diamond. Yossi Atuar, an expert polisher, has developed a virtual polishing system for white and colored diamonds. Here, he explains how the system works.
What is Virtual Polishing?
Virtual polishing is done using 3D software custom-tailored to the diamond industry. These systems take into account all the parameters, using proven scientific principles, to produce diamonds in different cuts.
The first principle, developed in the mid-90s, is based on the premise that every action performed on the polishing wheel can also be done on the computer. In short, the computerized planning can then be implemented on the polishing wheel. There is such high compatibility between the virtual polishing and the actual polishing that all a polisher has to do is follow the work plan – just like in any other advanced production and processing industry.
Alongside the planning of known and familiar models or the planning of new conventional models, the system also enables the user to plan new models that still lack specialized tools. It knows how to analyze light performance, including refraction, reflection, splitting and more. The sum total of the results simulates how the different factors impact the stone, including its color. Another advantage of virtual polishing is that the service is given online, without the need to mobilize the diamonds.
Planning Fancy Colored Diamonds
The system enables the user to plan both rough and polished diamonds in Fancy colors. The virtual planning of Fancy colored diamonds is naturally more complex. The system, however, has a distinct advantage over actual polishing “in the field”, as it allows the user to try different options without ever touching the diamond and risk losing valuable raw material.
In its pure form, a diamond is a colorless mineral. Fancy colors are created using the “trapped” chemical elements formed inside the diamond during its evolution, such as nitrogen (which gives the stone yellow hues) or boron (which makes it blue). Distortions in the diamond’s crystal lattice, in contrast, result in the loss of certain wave lengths, as is the case with pink diamonds. Planning diamonds in Fancy colors of this type is tougher than planning colored diamonds with trace elements. Polishers of pink diamonds are familiar with the color fluctuation when they work, and the difficulty in assessing the result– whether they use traditional methods for cutting or more advanced lab-based methods. Virtual planning enables the polisher to minimize the risk and dramatically improve the odds of succeeding.
In virtual planning, all the polisher has to do is send a scanned image of the stone via email, an image of the diamond from various viewpoints, analysis of spectroscopy (if available), description of the desired model, level of clarity and other parameters. The system is then calibrated according to the data, and the virtual polishing process begins. The process enables the user to control the architecture of the model and adapt it to the given rough stone. The user can experiment in different combinations of facets to achieve the maximum added value. At the end of the process, the model is imported to the decision making system for laser marking. The process of building the model is long and complex, and hardly resembles the automatic marking performed through the decision making system.
The Importance of the Diamond Image
Since the light reflected back is the sum of the light going in minus the absorption lines, the stone should be photographed against a white background. To enable the system to accurately measure the stone’s color, the diamond must be photographed using white light according to the industry standard – illuminant D65, which simulates natural daylight. Using any other background could affect the result. The image should be saved in RAW format, which captures all the unprocessed image data, although this is not a deal breaker. It is also important to control the amount of light exposure in the photo, so the image does not have “burnt-out” areas.
The Advantages of Virtual Polishing
All the current planning systems in the market operate on the principle that the 3D model of the polished stone is pre-prepared. All the computations done to achieve added value use the same pre-prepared model of polished stone. This is a precise, highly effective method as the user becomes more proficient in the system.
Virtual polishing enables the user to build a computerized model, just like he/she would while polishing using more traditional methods. The most salient advantage of computerized polishing is the user’s ability to control the model’s architecture, and add or subtract facets as needed. When planning a model for a specific rough, virtual polishing is essentially a customized polishing process that becomes increasingly more advisable as the value of the rough stone increases.
“All the virtual polishing tools I use were chosen from a wide selection of software, repeatedly tested from stones I personally polished. When dealing with diamonds in general and Fancy diamonds in particular, only virtual polishing enables a pre-planned, rational processing of the stone, as well as the freedom to experiment and be creative”, Atuar concludes.
Written by Iris Hortman