Lighting: Can good look bad, and bad look good?

[strmrdr]

te:[/b] 11/23/2005 9:27:12 AM
Author: oldminer

Someday, some person may invent a diamond specifically cut to look very special in low light.

[/quote]

There are several points im going to address but no time so ill stick to this one.
A good case could be made that as indoor lighting has involved so has diamond cut to deal with the indoor lighting conditions.
A lot of the old cuts with the broad reflectors are designed to perform in the soft and varying light of the time, candle and lamp light.
That is one area where a lot of todays diamonds are at the weakest performance wise.
So if anything that is reversed new cuts were develped to deal with stonger, harsher, and more direct indoor lighting not the other way around.
Today an average person will be in more lighting conditions than ever before.
Todays best cuts are designed with a balance to perform well accross a wide variety of light conditions simply because we spend time in a wider rangle of lighting contions than ever before.

In candlelight multiple experts have agreed the best modern round is the 8* with its huge pavilion reflectors, which goes back to the older cuts with there huge pavilion reflectors.
For the same reason a well cut emerald cut or asscher will kick any rounds fanny in candle light :}

what say you? :}

 

[Regular Guy]

Sorry, Dave, but what was actually your intention with this thread, anyway.

Date: 11/22/2005 3:09:48 PM
Author:oldminer
From time to time we read here that the kind and amount of lighting can fool the eye to an extent when it comes to judging diamond cut quality.

Although, and consistent with your introduction of Imagem, you frequently talk about the new age of judging diamonds based on light performance, but in your opening line, you talk about a diamond's cut quality, and the ability for one lighting environment or another to disguise this. Does this represent your real clothes, or ones you are long accustomed to wearing? If the quality of a cut may be revealed by a lighting environment, independent of the lighting performance seen at any given time, then the cut quality and light performance need not travel together.

Forget about the normal lighting environment...let's talk about the normal diamond shopper.

If a normal shopper, let alone a Pricescope shopper, determines they want to buy a diamond that is well cut, their choices invariably are not between poorly cut, and well cut. In truth, they will have a number of choices among several, if not many very well cut diamonds, typically. Although the idea of a system, set of principles, or strategy of any sort is attractive to shoppers who would like to sort out the very best from the best, it is these nuances where subtleties of lighting environment, I see by these most recent replies, should or at least could indeed be reasonably attended to. Figuring out the details of the difference....that's where the skills of experts on Pricescope can come in.

But...saying a badly cut diamond will only very rarely outperform a very well cut diamond? Really, what is the value in reviewing this?

 

[oldminer]

WRegular Guy;

I sure wish your responses were easier to digest. I''ll try to be responsive.

MY INTENTION WITH THE THREAD:
I wanted to emphasize that a subject often discussed her is how various possible lighting environments may make one diamond look a better than another, just as the cutting of a diamond might make a diamond perform a bit better in one sort of lighting environment than another.
It makes sense that these isolated cases exist, but in the real world where tens of thousands of diamonds are being graded, these weird cuts or unusual lighting environments don''t really mean much. The industry as a whole needs grading of cut and performance based on real world, commonplace lighting. If our eyes can''t tell the nuances, but a machine can, then we may want to use that scientific "normal" lighting environment exculsively for measuring performance (cut quality).

Of course, lighting can disguise performance or the lack of performance. A dark room does a 100% job. A dimly lit room does a very good job, too. Do you have a problem understanding this simple example? The diamond may be a superb cut, but it needs incoming light to show its beauty.

"Does this represent your real clothes, or ones you are long accustomed to wearing?"
What do you mean by this? I don''t have a clue.

"But...saying a badly cut diamond will only very rarely outperform a very well cut diamond? Really, what is the value in reviewing this?"
I don''t think you and I are reading the same thread. I have never seen a badly cut diamond that outperforms a well cut diamond. I said a badly cut diamond might appear to be equal to a well cut diamond in rare circumstances, like low light, but never better. I did also add that there may be odd ball cases that may exist where some really unusual thing happens, but in the commercial world where 99.9% of things are under control, there is no R&D money to be spent or wasted on truly unusual, weird stuff.

I wanted people who have read many threads and varying opinions on lighting environment to read that high performance diamonds always look equal to or better than less high performance diamonds even when our eyes alone cannot tell the differerence. It takes a discriminating device, one that measures very precisely the variables that determine performance. This is something our eyes don''t do as well as digital devices can be programmed to do.

A diamond''s cut quality should be a combination of proper physcial parameters which give high durability, very good polish and symmetry, and appropriate spread for weight ALONG with beauty which comes from high Light Perfomance. A super fine diamond needs all the attributes to be the best. A diamond with "problems" in its physical cut may still have very fine light performance, but it might not be good to say it is well cut in total. A diamond that is well cut physically, but for some reason lacks something in the Light performance department also should not be said to be among the very best.

Saying a diamond is "Ideal" incorporates physical shape and light performance parameters. In this thread I was addressing light performance and not physical parameter issues.

Hope this clears the air.

 

[valeria101]

Date: 11/23/2005 11:46:25 AM
Author: oldminer

Of course, lighting can disguise performance or the lack of performance. A dark room does a 100% job. A dimly lit room does a very good job, too. Do you have a problem understanding this simple example?

Clear as day. It may be an unusual example among complaints that too strong ''shop'' lighting not darkness is what usually blurs the line between more or less expensive shades of cut quality.



[...] there is no R&D money to be spent or wasted on truly unusual, weird stuff.

Happy to hear this

I wanted people who have read many threads and varying opinions on lighting environment to read that high performance diamonds always look equal to or better than less high performance diamonds even when our eyes alone cannot tell the difference. It takes a discriminating device, one that measures very precisely the variables that determine performance. This is something our eyes don''t do as well as digital devices can be programmed to do.

Sounds great to me, up to a point. Probably just some pesky semantics that show way too much in a post. I am sure digital devices can see beyond human capability, but ... what''s the use of performance that cannot be seen?

I am not saying that this is a fair reading of the message - only the first that comes up. I suppose one can always make a case for good beyond the ''eye of the beholder''. Is it the case here?

 

[squarediamondlove]

Date: 11/23/2005 8:11:05 PM

Sounds great to me, up to a point. Probably just some pesky semantics that show way too much in a post. I am sure digital devices can see beyond human capability, but ... what's the use of performance that cannot be seen?

I was wondering this myself. Is this allong the lines of "mind clean stones." That even though you cannot discern the difference, you can appreciate the perfect makeup of one stone over another.

Also, from the perspective of surface beauty (speaking solely of external appearance and not the inherently perfect makup), wouldn't your argument imply that the key factor is diamond's performance in different lighting conditions?

Also, would diamond grading change if our primary concern would be diamond's performance in various lighting conditions?

One more: I wonder if there is more variation between princess cuts (of fancies in general) when it comes to different lighting conditions. I can see rounds being more consistent under different lighting conditions (a better stone will look better in every environment) than a princess. What do you think?

 

[valeria101]

Date: 11/24/2005 3:04:52 AM
Author: Kaleidoscopic

I was wondering this myself. Is this along the lines of ''mind clean stones.'' That even though you cannot discern the difference, you can appreciate the perfect makeup of one stone over another.

... or maybe not.

one would need to be told to think these differences that aren''t there. I am a bit skeptical, since this flow of information can only be one-sided.



Also, from the perspective of surface beauty (speaking solely of external appearance and not the inherently perfect makeup), wouldn''t your argument imply that the key factor is diamond''s performance in different lighting conditions?

Don''t understand... Assuming ''surface beauty'' is finish (polish & face meet symmetry), the rest is not clear at all. What these have to do with the lighting conditions?



Also, would diamond grading change if our primary concern would be diamond''s performance in various lighting conditions?
What else? Arbitrary grades can be made up any day.



One more: I wonder if there is more variation between princess cuts (of fancies in general) when it comes to different lighting conditions.

There is more variation in the cut of fancies because there are simply allot more variables involved. If you''d want to give a complete description of a round cut (abstract model), you can get away with a dozen numbers. For a princess cut there are twice that or more parameters. Rounds are the simplest cut.



I can see rounds being more consistent under different lighting conditions (a better stone will look better in every environment) than a princess. What do you think?

Which rounds? Perhaps some rounds and some fancies look better or more consistently better throughout. That should be the point of a good cut as far as I understand

Anyway, I would not go about discussion lighting conditions so much because diamonds have to face them all anyway. And I doubt the usual cuts can be tweaked so that they appear strikingly gorgeous in one real-life environment and truly butt-ugly in another. I am thinking of casual wear, not someone walking a loose diamond around the house to hunt for ''real life'' lighting just so.

From this perspective, I really like that simple concept of ''light return''. The shortcomings are easy to understand and the balance of light reflected does not depend on input. Why would high light return be bad in any lighting conditions? ''Guess not. That highest light return looses too much contrast also makes sense regardless of lighting - and makes a comfortable concept because of that. Fire I don;t know how it works or doesn''t with lighting - there must be some way to understand this, but two of three cut metrics covered can''t be that bad.

My 0.2


I am still with Serg''s note that there is need to clarify the use of ''lighting conditions'' as model parameters and casual wording. IMO, it is that confusion that makes the topic interesting, not something more profound.


Anyway. I am not an expert and this is getting intricate

 

[strmrdr]

a uniformly bright stone is not the best looking stone in a lot of lighting conditions.
It will act as a flat mirror.
This is where it gets complicated when you start considering contrast brilliance.
The various h&a rounds are considered the best because they provide a high light return with symmetrical contrast in a pleasing amount.

its not as simple as high light return == beauty accross a wide range of light conditions.

Which comes back to tuning a diamond for different light conditions and different balance points.

Remember the thread Jon did with the 2 princess cuts and a lot of people selected the less bright but better contrast stone as the better diamond when looking at it in person?

Just like you cant only consider diamond quality in one light condition you cant only consider one aspect of diamond performance.

 

[squarediamondlove]

Date: 11/24/2005 10:53:45 AM
Author: strmrdr


Remember the thread Jon did with the 2 princess cuts and a lot of people selected the less bright but better contrast stone as the better diamond when looking at it in person?

I''d love to know the link to this post

 

[valeria101]

Date: 11/24/2005 10:53:45 AM
Author: strmrdr

a uniformly bright stone is not the best looking stone in a lot of lighting conditions.
It will act as a flat mirror.


I must have wrote that ''light return'' is not the end-all...
The good part for which it got mentioned is the simple concept independent of viewing conditions. Of the physical measurements used for cut grading this is the simplest (and first used, I guess).



Its not as simple as high light return == beauty across a wide range of light conditions.

... It is not as simple as ''beauty'' = LR in any light conditions. I don''t know what light conditions have to do here anyway.



Which comes back to tuning a diamond for different light conditions and different balance points.

I can''t agree. I think you are talking about ''light conditions'' as a model. One can''t escape accounting the crazy detail when constructing a virtual environment (DC). No one is going to move house just to have proper diamond-viewing conditions.

Just like you cant only consider diamond quality in one light condition you cant only consider one aspect of diamond performance.

Ok, I guess this sentence sums it up. This cannot be right. Unless the ''light conditions'' are something extremely simplified and/or controlled. Which happens in photography (with luck) and models (by necessity) but that is not exactly the desirable side of photographic or VR imagery.

Serg put it pretty well. I still consider his post as the one needed clarification of this entire discussion of light matters. Perhaps we can dissent just once ...

 

[strmrdr]

no Im not talking about light conditions as a model nor DC but as simple as office lighting vs bright sunlight vs shaded sunlight in the real world.

diamonds that look similar in bright sunlight may not look anything alike in office lighting and the reverse.
Different aspects of diamond performance come into play in different lighting.
For example ask the owners of h&a diamonds if the arrows are visible all the time. No they arent depending on the lighting even in short lgf% diamonds.
When the arent visible the contrast they supply isnt in play in that lighting environment.

Put them in another lighting environment the arrows become dark and provide contrast brilliance.

No diamond will perform and look the same across a wide range of light conditions it will always have a different look depending on the lighting.
That will always be so until a diamond is cut with an internal light source bright enough to overwhelm the effects of surrounding light.