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- Aug 14, 2009
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I have a question from the discussion that came up in my other thread on precision cutting here, that I'd prefer to ask in a different thread so as not to derail that one.
Forgive my lack of eloquence - but here is my scenario: I give a cutter three lumps of rough, identical in every way except colour. One is fit for a 1ct I, the second for a 1ct K, the third for a 1ct M. I ask the cutter to cut each into a 1ct RB worthy of the GIA EX grade (so using those specific known constraints) that best "evens out" the "apparent colour" differences - so that when you look at each stone face-up in diffuse office light, they look to be the same slightly tinted colour (like the way FCDs are graded by apparent face-up colour, which a cutter can manipulate).
1. Is this *possible*?
2. What would be the cutter's best choice - and maybe Diagem if you will indulge me here, since you so kindly invited questions in my other thread
how would you choose, and how would you verify your choice?
My first instinct is to advise cutting the M into an RB w/ large table, as shallow crown/pavilion combo as I can get away with within the GIA EX constraint, very thin mains, thin girdle plus paint the crown - again, as much as I can get away with. Because my GIA H with such proportions was much *whiter* to my eyes than my other GIA H of similar size w/ short lgf, higher crown, thicker girdle...
BUT, at some point on that D-Z spectrum smaller virtual facets spitting out splintery little coloured low-energy twinkles result in colour saturation rather than colour minimization... or, at least, that's how I understand it. Where is that line? Is it predictable? Does it change from person to person? I know that the discrepancy in apparent colour face-up between an H EightStar type RB and an H radiant designed to highlight colour would be far less than the face-up apparent colour discrepancy between a Y/Z EightStar and a Y/Z radiant designed to highlight colour, thanks to the increase in absorption w/ every incremental increase in path length. And I saw last year that to my eyes a J emerald cut showed more body colour face-up to my eyes than a J AGS0 3chevron princess of similar weight, while a gorgeous chunky W/X OEC showed far less colour face-up than a slightly smaller S/T radiant - but obviously these are different design patterns, so it could be comparing apples to oranges - or to elephants. Too bad they didn't have an S/T AGS0 princess, that would've been enlightening!
Rhino I see that GOG has a couple of 1.2ct R AVRs and a 1.26 Q H&A RB - would share your thoughts on which, in your opinion, faces up "whiter" - in what types of lighting? I would be really interested to hear what you think. What about your K/L/M AVRs and H&A RBs?
Forgive my lack of eloquence - but here is my scenario: I give a cutter three lumps of rough, identical in every way except colour. One is fit for a 1ct I, the second for a 1ct K, the third for a 1ct M. I ask the cutter to cut each into a 1ct RB worthy of the GIA EX grade (so using those specific known constraints) that best "evens out" the "apparent colour" differences - so that when you look at each stone face-up in diffuse office light, they look to be the same slightly tinted colour (like the way FCDs are graded by apparent face-up colour, which a cutter can manipulate).
1. Is this *possible*?
2. What would be the cutter's best choice - and maybe Diagem if you will indulge me here, since you so kindly invited questions in my other thread
how would you choose, and how would you verify your choice?My first instinct is to advise cutting the M into an RB w/ large table, as shallow crown/pavilion combo as I can get away with within the GIA EX constraint, very thin mains, thin girdle plus paint the crown - again, as much as I can get away with. Because my GIA H with such proportions was much *whiter* to my eyes than my other GIA H of similar size w/ short lgf, higher crown, thicker girdle...
BUT, at some point on that D-Z spectrum smaller virtual facets spitting out splintery little coloured low-energy twinkles result in colour saturation rather than colour minimization... or, at least, that's how I understand it. Where is that line? Is it predictable? Does it change from person to person? I know that the discrepancy in apparent colour face-up between an H EightStar type RB and an H radiant designed to highlight colour would be far less than the face-up apparent colour discrepancy between a Y/Z EightStar and a Y/Z radiant designed to highlight colour, thanks to the increase in absorption w/ every incremental increase in path length. And I saw last year that to my eyes a J emerald cut showed more body colour face-up to my eyes than a J AGS0 3chevron princess of similar weight, while a gorgeous chunky W/X OEC showed far less colour face-up than a slightly smaller S/T radiant - but obviously these are different design patterns, so it could be comparing apples to oranges - or to elephants. Too bad they didn't have an S/T AGS0 princess, that would've been enlightening!
Rhino I see that GOG has a couple of 1.2ct R AVRs and a 1.26 Q H&A RB - would share your thoughts on which, in your opinion, faces up "whiter" - in what types of lighting? I would be really interested to hear what you think. What about your K/L/M AVRs and H&A RBs?
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