The American Ideal Cut Diamond
Photographs and Analysis of its Superior 'FIRE" Power
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| Here is a photograph of an American Ideal, round brilliant cut diamond shown from a viewing angle of 40 degrees at six different magnifications, 2.5X-10X. This photo displays the American Ideal's potential for fire in high contrast illumination. |
Here you will see for yourself the superior properties of diamond beauty present in the American Ideal--- especially the property called fire. You will learn aspects of the American Ideal cut's optical performance that result in its superior beauty in many natural lighting environments away from the razzle-dazzle of jewelry store lighting.
In discussion about diamond beauty, words are sought that describe what our eyes see when viewing a diamond in different lighting environments. Diamond beauty results from the visual interaction between the diamond, our eyes and the panorama of light surrounding the diamond. The properties of a well-cut diamond enable it to gather light from a broad range and number of surrounding directions and angles. The Ideal diamond captures the surrounding panorama of light reflecting to the viewer from within the diamond a kaleidoscopic mosaic of reflections possessing vibrancy often described as the diamond's 'life'.
Central to diamond beauty are the qualities and quantity of these reflections coming from the diamond to the viewer's eye. The diamond's visual performance, reflecting and refracting the surrounding light to the viewer, is the beauty that Gabi Tolkowsky, grand nephew of Marcel, refers to when he proclaims "The beauty is everything". This unique light performance has stirred emotions and engendered devotion unsurpassed by any other gemstone.
The answer is fire, dispersed by the diamond from open sky daylight, which was the source of this diamond's illumination. The daylight was broken up to get this degree of fire in a manner that often happens in natural viewing environments.
This first photo illustrates the American Ideal cut's beauty with respect to both brilliance and fire. The American Ideal possesses a superior combination of the contrast quality of brilliance and the light return quantity of brilliance in lighting favorable to these aspects of diamond beauty. The Ideal is also superior with respect to fire when the lighting is favorable to this important and often unheralded aspect of diamond beauty.
Notice that this first image has captured the seldom-present green fire as well as the more often observed, blue, yellow and red fire. Blue, yellow and red fire are present in the following, second diamond photograph.
This diamond photograph was taken under a similar open sky as was the first, but with my head and torso providing the break up of the diffuse daylight
illumination enabling this display of fire. The following photo shows the partially obscured, sky light illuminating this diamond.
The diamond's illumination by bright, overcast, sky light, partially obscurred by my silhouette.
Were you present under this overcast sky, you would have seen first hand the fire you see captured by the camera in these photographs.
The second diamond photograph and the ones to follow support the importance of the discovery that the American Ideal's combination of pavilion and crown main angles is on the verge of obstruction by the viewer's head resulting in the blocking of table-to-crown-main and crown-main-to-table light rays.
Interacting with the obstruction from the viewer's head and torso, Ideal diamond pavilion and crown angle combinations result in a greater contrast quality of brilliance. Equally important, these Ideal combinations also give rise to the blue fire observed in the diamonds in photograph two and those that follow.
The reflections from the pavilion main facets in the American Ideal alternately flash from dark to bright to dark when the diamond is tilted from the normal,face-up view, giving rise to large flash scintillation and contrast brilliance. This mosaic of larger reflections is reminiscent of the larger high contrast sparkle and fire many prefer in Old European and Old Mine cut diamonds from times past.
As seen in these photos, blue fire flashes from these table-to-crown-main and crown-main-to-table reflections in their transition from dark to bright. The dark-bright, high contrast edge in this type of illumination results in the fire in these diamond photographs. (We will leave for another article the detailed explanation of how high contrast edges give rise to fire.)
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These photographs, which are magnified by the camera lens, are what is seen in miniature when observing the diamond in the face-up or normal viewing position and from tilted angles. They were adjusted for exposure and contrast to reflect the true appearance of these diamonds in the various lighting environments. Photography fails to match the greater range of human vision. The fire and brilliance actually observed in these diamonds, under these lighting conditions, exceeded the beauty you see reproduced here. The advantage over the human eye that these photographs give us is the opportunity to analyze at large magnification the details of that observed beauty. |
Lighting environments, such as the uniform hemisphere illumination used to measure light return or the single point source of light used in some measures of fire do not account for the effect of the viewer partially obscuring the diamond's illumination. They miss its importance to explanations of aspects of the American Ideal's superior beauty with respect to fire as well as contrast brilliance. There is more that these photographs demonstrate concerning the superiority of the American Ideal cut.
As we celebrate the cutting achievement that is the American Ideal, we need to credit the very best of the diamond cutting profession. My research, photography and writing provide testimony to their knowledge and skill. I hold in high regard those diamond cutters from the American innovator, Henry Morse (the first to cut to ideal pavilion and crown angles) in the 1860's through to today's American Ideal cutters, who have advanced this crowning achievement in diamond cutting .
Michael Cowing, MS, FGA, A.S.G.
PS: For students and lovers of diamond optics and beauty, here is a partial analysis of the mosaic pattern of reflections including the blue fire in the
following two and a quarter carat round brilliant cut diamond.
We are viewing this diamond at a slight tilt from the normal, face-up position. The mosaic pattern of reflections from the octagon shaped table contains slender, needle like reflections from the eight pavilion main facets, which meet at the center of the pavilion at the 'culet'.
The two reflections at two and seven o'clock display blue fire, the two at one and five o'clock are dark, the one at nine-thirty is bright and those at four, eight and eleven are partially bright and partially obscured by other reflections. On both sides of the dark main reflection at one o'clock are triangular reflections of blue fire.
Look at the following photograph of one of the diamond ring's four prongs. You will see mirrored in that prong the panorama of illumination surrounding this diamond. We can point out, from the illumination environment reflected in this prong where each of these pavilion main reflections comes from.
The diamond's illumination is mirrored in its prong. The two dark main reflections at one and five o'clock are coming from high angles, where the silhouette of my head and outstretched hand is obscuring the bright sky light.
The bright reflections are coming from the bright sky light between my silhouette and the dark silhouette of the surrounding trees.
The reflections of blue fire are coming from high angles right at the edge of the dark-bright transition from my dark silhouette to the bright skylight.
Incidentally, the brown reflection at four o'clock in the diamond's table is coming from the brown stool upon which the white ring box is sitting. You can see the brown stool reflecting in the prong photograph.
Because this brown reflection in the diamond's table comes to the viewer from below the diamond, it is an example of what is traditionally called 'light leakage'. It would be clearer to describe light leakage of this sort as reflections from beneath the diamond.
