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Seeing is believing?
This optical illusion shows how our perception can corrupt a signal received by the eye. Lateral inhibition results from the ability of one part of the retina to inhibit the peripheral vision signals from another. (Seeing the Light: Optics in Nature, Photography, Color, Vision, and Holography. Falk D., Brill D., & Stork D. John Wiley and Sons, New York, 1986).
Humans do not ‘see’ in photo’s. Through survival we have evolved a method of vision primarily based detection of movement and recognition of patterns. The optical illusion shown illustrates that perception is not related to reality. Human physiology raises questions about proposed and existing methods of direct assessment.
Try looking at the flashes of fire in a diamond while you hold it very still. First look with one eye, then with the other, followed by looking with both eyes. Repeat this experiment in a variety of different lightings. It is quite scary to contemplate the level of complexity of such a simple experiment. It is unlikely any machine could ever duplicate what you see, let alone have the flexibility to see as another person does.
Contrast enhances perception of saturation
Our eyes seek edges and boundaries between contrasting hues and tones. This is ‘programmed’ into us as part of the quest for survival and to bring meaning to our world. How we then assess the pleasure or emotions we experience from our observations results in an individual experience or perception. For instance the inability to find an edge in a Jackson Pollock painting made the artist wealthy, yet I find this visual trickery annoying and a manipulative misuse of art.
International diamond dealers know people from different geographic, cultural and socio-economic markets favour different proportions and looks in diamonds. Differences in buyer preferences make it appropriate that a diamond cut-grading system would assist vendors distinguish demand from various market segments. The HCA grading system addresses those issues.
Consumer perception of diamond beauty and desirability differs from that of many experts who examine diamonds with lenses and flood-lit back lighting environments. In short, sellers have learned how not to look the way buyers do; a classic mature marketing mistake.
This diversity of consumer preferences may mean there may be no rational scientific solution to the “ideal cut” dilemma, and no true way to measure an individual diamonds performance for more than an individual buyer. I hope that my contribution to this subject has bought an appropriate balance of observation of both diamonds and diamond consumer behaviour and preference. Having had the benefit of some training in the behaviour of light, and an early scientific education, I hope to have had enough understanding of the issues to support my observations with some credible evidence. Some people will challenge the lack of scientific rigour and reproducibility of the methods used to design the scores in HCA. They are welcome to do so; I have never maintained any pretence of being a scientist. All I have is a well developed ability to ‘look good’ and challenge assumptions. But many of my results have been confirmed by true scientists.
So be it if the methods and results of this cut study are unscientific, if the results are wrong then I will enjoy the search for better solutions. Criticism is a friend, not a foe in the quest for continual improvement.
Is Light Return Brilliance?
One of the most complex problems that dogs me is the relationship between light return and scintillation. I am quite prepared to consider that there is no way to measure brilliance. Light return is a quantifiable thing, but brilliance is a human variable.
This simple experiment that shows the effects of contrast was proposed by my friends (the real Scientists) at Moscow State University.
Consider some of these variations to this experiment:
- Would the viewing distance affect the result?
- Does the observer’s eyesight play a part?
- Would the light type and source type affect the experiment?
- Does movement change the results?
- Would bars, triangles or circles change the result?
- Would colors give the same result?
Beauty and desirability are to some extent in the eye and mind of the beholder. Different people will prefer different diamonds. HCA demerits diamonds with sub-optimal performance, such as light loss out the pavilion, excessive head-shadowing or fisheye effects etc. It then also sets out to describe three groups of diamonds that have appeal to various buyers.
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