A discussion about opposite facets

[strmrdr]

btw if you compare the IS to ASET it will show you that very shallow asschers act the same way as shallow/shallow rounds when it comes to obstruction.
much better in a pendant.

 

[stebbo]

Date: 3/23/2007 2:45:22 AM
Author: stmrdr

The goal isnt maximum light return its a pretty diamond (doing that while returning as much light as possible is how ever a good goal.

Feel free to shoot me, I value your input as I'm seeing this all different to conventional wisdom.

Agree with your line above, but let's waste as little light as possible and distribute it all back in a pretty way. Maybe we'll emanate 200 more-intense flashes or maybe 400 less-intense, maybe more pin or less broad flashes, maybe more dispersed or not, but light wastage can only mean less 'power' and power is everything if it's used correctly.

Get DC and start designing diamonds.
Get the most red you can in the ASET view eliminate all the blue and green you can.
Then play it in the video modes, it looks like caca when compared to a more balanced diamond.

Exactly, because maximizing red in a ASET view is maximizing light return in one direction only, not maximizing total light return. Too much red returned in one direction will mean red has been stolen from other directions, so we'll have a dead diamond, albeit one with a blazing sweet spot.

It's an infinite and impossible task in DiamCalc to maximize 'total' light return using the ASET view.

The best optical symmetry is achived when the light paths for a beam striking any given point is the same path pattern and distance for any of 8 identical points on the diamond.

Do that without physical symmetry on an 8 fold symmetry object and report back.

My argument here is perfect physical, or geometric symmetry should not be imposed on a natural substance, unless you just want to buy a perfectly geometric object. How constant is the refractive index throughout the diamond, for all frequencies of light, how constant is the attentuation, for all frequencies of light, how constant is the air/diamond boundary given that different facets can take on different levels of polish. Only major inclusions may affect light performance significantly, as do only reasonable geometric symmetry deviations, but how much might geometric symmetry have to be compromised to cater for inclusions in order to maintain optical symmetry? Then we have graining, cleavage planes and possibly slight color changes further saying "I'm not a perfectly consistent material, so why are you trying to me take on a perfect geometric shape - work with me."

 

[strmrdr]

*bang* lol

all red aset:
if you want the most light return you need to draw light from the brightest source in the environment your in.
Which is generally red in ASET.

overall diamond "looks"/"personality" is a balance of several factors not just one thing.

For example the white light return and overall brilliance of an RB kicks a oec and asschers all over town but too many people the oec and asscher are the more beautiful diamond.

As far as your technical question the answer is at this time there is very very little research and data available in those areas.
Both the AGS and GIA grading system ignore inclusions and reflective and absorption differences.
In 10-15 years we may have the answers to those questions and today's information and systems will be considered a joke.
For example its just in the last handful of years that the ability to even measure to the best cutting level of the cutters has existed. (its questionable if it exists today)
Its a young science that combines several fields, vision, material, optics and cutting all have to be considered.

by definition a RB cut is 8 fold symmetrical which means you should be able to cut it in 8 pieces and interchange them and get the same resulting object.
You cant do that with wide variances.

You do raise an interesting point about real optical symmetry vs hearts and arrows.
They are really a by product and an accident not an original design goal of the cut.

How would you measure the true optical symmetry of a diamond vs using the hearts?

 

[strmrdr]

btw this is way kewl to be thinking outside the box.
Thanks stebbo.

 

[stebbo]

Date: 3/24/2007 6:51:03 AM
Author: Garry H (Cut Nut)

Some problems Stebbo:

1. your logic is founded on light being a ray format. But most of the time we see a diamond the light is behaving as a beam because it is coming from a small glabe and radiating, or a large window from many directions at once etc

But a beam is just a collection of rays correct? Can you explain a bit further please?

2. The assumption is that if the light ''misses'' the opposing reflector that it is lost. This is wrong.

No, not assuming that at all, otherwise a diamond would be very dull as I don''t see the opposite facet having anymore importance than any other (same-kind) facet (given the omnidirectional nature of diffuse light). I was trying to understand the logic behind the "opposite facets being matched is good" line I hear tossed around every now and again.

3. The idea that there are bigger flashes is good (based on roiund brilliants) is wrong because there are many cuts where a smaller flash is desired - eg princess cuts have much smaller flashes and some peple prefer that, Asschers have fewer and bigger and others prefer that.

Not assuming this either. I''m talking about maximizing total light return in directions that can be appreciated. That total light can be distributed broadly or more pin-like.

4. our eyes, the ambient brightness and pupil diameter, the background the diamond is seen from - all these things have an impact on what we see and introduce variables way beyond your nice simplification.

But does that change the goal of maximizing total light return? It might be maximum total light return assuming 75% of the time observers are in office/home lighting, 25% daylight, or maximum total light return assuming observers wear dark clothes 90% of the time, or there''s a 25% chance it''ll be perched up high on a Tiffany. Even though different scenarios require different designs, maximum total light return in that scenario is desirable as I see it.

Another thought: Will more intense fire be seen from a candle, or from a more intense halogen bulb of similar size (in the typical room where that direct light leads creates some ambient lighting)? Does the decrease in pupil diameter in the halogen case mean that fire won''t seen as more intense?
I don''t think so, otherwise it would be a waste of time having super bright lighting in a jewelry store, as our pupils would just be closing down anyway.

 

[strmrdr]

Jewelery store lighting:

If the super bright lighting was diffused our eyes would adjust then it wouldn''t help but its directional and aimed at the diamond.
Iv seen setups where the sales person was encourage to move to a certain position based on the customers height so spot lights would go over the customers shoulder onto the diamond.
They went as far as having staggered lighting so a shorter person standing next to a taller person would both have the light over their shoulder so if a average height lady was standing next to an average height guy both would get the full effect of the lights.

Dark lighting behind the sales person is used also, the eyes adjust to the dimmer light then when they look down at the bright lights hitting the diamond it looks even brighter.

Check out the lighting at a high end store some time they spend mega bucks getting the lighting just right.
They are far more tricky than just having bright lights.

 

[Garry H (Cut Nut)]

Date: 3/26/2007 8:43:34 AM
Author: stebbo

Date: 3/24/2007 6:51:03 AM
Author: Garry H (Cut Nut)

Some problems Stebbo:

1. your logic is founded on light being a ray format. But most of the time we see a diamond the light is behaving as a beam because it is coming from a small glabe and radiating, or a large window from many directions at once etc

But a beam is just a collection of rays correct? Can you explain a bit further please? stebbo read the section in the Letters to the Editor of the Australian Gemmologist in the Journal section that uses images of the sparkles from a diamond on an imaginary black dome - and you should understand what I mean. The sun has rays, a haolgen or candle has beams. http://journal.pricescope.com/Articles/50/5/Letter-to-the-Editor-of-the-Australian-Gemmologist.aspx

2. The assumption is that if the light ''misses'' the opposing reflector that it is lost. This is wrong.

No, not assuming that at all, otherwise a diamond would be very dull as I don''t see the opposite facet having anymore importance than any other (same-kind) facet (given the omnidirectional nature of diffuse light). I was trying to understand the logic behind the ''opposite facets being matched is good'' line I hear tossed around every now and again.

3. The idea that there are bigger flashes is good (based on roiund brilliants) is wrong because there are many cuts where a smaller flash is desired - eg princess cuts have much smaller flashes and some peple prefer that, Asschers have fewer and bigger and others prefer that.

Not assuming this either. I''m talking about maximizing total light return in directions that can be appreciated. That total light can be distributed broadly or more pin-like.

4. our eyes, the ambient brightness and pupil diameter, the background the diamond is seen from - all these things have an impact on what we see and introduce variables way beyond your nice simplification.

But does that change the goal of maximizing total light return? It might be maximum total light return assuming 75% of the time observers are in office/home lighting, 25% daylight, or maximum total light return assuming observers wear dark clothes 90% of the time, or there''s a 25% chance it''ll be perched up high on a Tiffany. Even though different scenarios require different designs, maximum total light return in that scenario is desirable as I see it.

Another thought: Will more intense fire be seen from a candle, or from a more intense halogen bulb of similar size (in the typical room where that direct light leads creates some ambient lighting)? Does the decrease in pupil diameter in the halogen case mean that fire won''t seen as more intense?
I don''t think so, otherwise it would be a waste of time having super bright lighting in a jewelry store, as our pupils would just be closing down anyway.