RED REFLECTOR PICTURES

What am I looking at when I see these images?

Below is an in-depth understanding of these images or you could go through this quick guide powerpoint.

These red images are a test to see how much light return a diamond has and how much light leakage a diamond has. The tool used is a lightscope. There are a few various versions and that's why you see here two different types of images here. The first one which is called the lightscope or DiamXray has 3 colors, red, black, and white. The other which is called the ASET® has 4 different colors, red, green, blue, and white. In both images the red and white colors serve as the same function, red being light return, and white is light leakage. The blue and black colors both serve as contrast and the green in the ASET®  serves as light return but less intense than the red color. These colors all serve a different purpose They show where the light is drawing from. All the facets of a diamond will function in either one of two roles. Mirrors or windows. It is primarily the combination of both pavilion and crown angles that will determine whether the facets will function in either role but generally speaking the crown facets primarily function as receptors of light, allowing that light to pass through within the diamond and it is the pavilion facets that should function in the primary role as the mirrors reflecting light out through the crown into the face of the observer. The path of light traveling and bending through a diamond is called light refraction. Let's follow a beam of light as it travels throughout a diamond. This is made possible with ray tracing software developed by Moscow State University and is a very sophisticated application for tracking and observing light behavior in diamonds with any given set of proportions, either through a scan and model created in another application (like Sarin, Helium or OGI) or you can input the parameters manually. So just to recap.

Red: Light Return

Black or Blue: Contrast

Green: Light Return (But Less intense than the Reds)

White: Light Leakage

This sample stone is one that is cut to *super ideal* specs. 34.5? crown angles, 40.8? pavilion angles and a 57% table.

1. The initial ray is entering the table facet at 100% intensity.

2. 17% is reflecting off the surface of the diamond. This external reflection is often referred to as luster or glare.

3. The remaining 83% is refracted within the diamond bouncing off 2 pavilion facets and a crown bezel facet before exiting.

4. Before leaving the crown 19% of that ray bounces within the diamond again and peters out before exiting (shown in sky blue).

6. 100%, less 17% (external luster/glare), less 19% stray refraction, leaves 64% exiting through the crown as dispersion/brilliance.

In short, of 100% light that enters the diamond 81% is reflected and refracted off the facets and back into the eyes of the viewer. For diamonds, THAT'S EFFECTIVE considering its only 1 single beam amongst many that occur simultaneously.

In the below image look what happens when we alter the crown/pavilion angles to non ideal standards. The only light exiting the crown now is the glare at 17%. All brilliance/dispersion is lost out through the bottom. NOT GOOD.

1. Mirrors & Windows

   Observing and Interpreting the Colors: Red Reflectors

   One basic function then that all red reflectors show us is what role the facets are functioning as (ie, mirrors or windows). If the facets are functioning as mirrors we will be able to observe predominantly all reds and blacks as we look through a FireScope, SymmetriScope, DiamXray or IdealScope. Here are a few examples of various diamonds we sell showing excellent light return to poor light return with the Diamxray accommodating their respected Aset® underneath. The first 2 diamond qualities (Ascendancy & Platinum) are our biggest selling diamonds. We'll decipher the information from these images in more detail below. Before we do however some basic explanations are in order.

   

   When a diamond is viewed by a person in a normal viewing environment there should be 2 different phenomena that should be observed.

   A. Facets that are reflecting back light.

   B. Facets that will reflect back the reflections of things in the atmosphere such as the person's reflection within the stone that is blocking or obstructing light.

   Hence this DiamXray image translates into an appearance in bright hemisphere lighting akin to the photograph next to it.

   

   Note that the bright areas within the diamond's photograph appear as reds in the DiamXray image and the blacks appear as darker areas.

   This obstruction is also referred to as obscuration and accounts for what we could also call "head/body shadow". The graphic below demonstrates this as the reflection entering the stone between the black arrows are a reflection of Sarah's head & body. Red would be atmospheric light entering at all other angles.

   

   The amount of obscuration then depends upon the size of the viewers head or how big the object is in front of the diamond that would obstruct light from entering. Most gemologists agree that 25-30 degrees of obscuration accurately accounts for most head sizes and a good standard upon which to base this obstruction on.

   The Ideal-Scope accounts for 25 degrees of obscuration. DiamXray & FireScope, 27 degrees. The new AGS ASET, 30 degrees (although algorithm's for 30 and 40 degrees will be considered in AGS' final grade as well as tilt factors). This observance of light and dark is what causes contrast patterns within the diamond and is a major contributing factor to the brightness or brilliance of the stone (as discussed in our chapter on brightness).

   Going back to an example image lets examine the details of the image and how it translates to human eye observation. A GIA Very Good on the left with an Ascendancy on the right.

   

   As observed in this image you can see four primary colors. Here are the colors and their interpretation.

   1. BLACKS = light, or more accurately obstruction entering and exiting at high angles. As pointed out above, this represents obscuration (head shadow) however when the diamond is rocked and tilted in normal fashion these blacks become some of the most intense reflectors of light giving off strong fire and scintillation in direct light conditions (not hemisphere). In diffuse light conditions are points of contrast contributing to brightness and what would be called dynamic scintillation.

   2. DARK REDS = light being returned to the viewers eyes at the strongest intensity (face up view).

   3. LIGHT REDS = light being returned to the viewers eyes at a weaker intensity. The paleness of the reds indicates the weakness at which the light is being returned to the viewer and generally only observed in direct or strong lighting conditions. (note: The contrast between light and dark reds is a feature best seen in DiamXray photography. Other reflectors do not show this contrast but generally show all reds at the same saturation).

   4. WHITE = blatant leakage. Whites indicate facets that are functioning as windows as opposed to mirrors and contribute to leakage contrast as observed around edges (perimeter) of the diamond.

   What is desired is a nice balance of blacks and reds with as little white as possible. The above image represents what is perhaps the loosest standards
   AGS will accept in their new cut grading system and that is good.

   Here is a comparison of a diamond exhibiting good light return with good contrast next to a stone that's well ... a pooper. :) The stone on the right is exhibiting too much light leakage contributing to less brilliance and the lack of blacks indicate weak fire, contrast & scintillation. The actual photographs are taken in hemisphere lighting and accentuate the differences in appearance as seen between the two.

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2. Optical Symmetry

   Optical symmetry refers to the alignment of the facets on a 3-dimensional plane and demonstrates the precision to which the diamond has been cut optically. In order to do this, a cutter must be familiar with what proportions and symmetry produce the finest light transmission and appearance. While optical symmetry can be viewed in a Hearts & Arrows viewer we can also observe this phenomenon quite easily through reflector technology as well.

   Here is an example of two ideal cuts. The diamond on the right not only has superior light return but introduces the metric of optical symmetry to the equation. The diamond exhibiting the superior optical symmetry is more finely crafted, takes approximately 4x the amount of time to cut and results in what is perhaps one of the most precision cut diamonds with incredible optics while the stone on the left was probably cut in roughly 1 hour or so.

   

   Unfortunately no metric for optical symmetry is taken into account in the new cut grading systems and we personally feel this is a disservice to those factories who are taking their time to cut precision diamonds. As noted earlier this optical symmetry can also be viewed through a Hearts & Arrows viewer. Below is a photograph of this same diamond through a Hearts & Arrows viewer. The arrows are obviously what is seen in the face-up shot, while the Hearts are observed in the face down (upside-down) position. Reflectors are good devices for displaying this component of optical symmetry. Here is a photograph of a diamond with superior optical symmetry next to a standard ideal in hemisphere lighting..
    

   In GIA's observation testing a fairly equal amount of people found the 2 to be equally as beautiful which is primarily why no metric for optical symmetry was included.

3. The optical results of both Slope & Azimuth Angles

   Of all the reflectors in use there is one in which we can actually photograph the optical effects of both "slope" & "azimuth angles" and how far they deviate from "ideal" which can be observed in the face-up position.

4. Slope Angles

   For clarification, there are actually 2 angles that each facet is cut to. One would be considered the slope angle, the other being the azimuth angle. When you read the results of an AGS Report or a Sarin/OGI Report you are strictly seeing slope angles.