Which would you choose?
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strmrdr
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I reposted this for Rhino with the images working.
It is him talking here not me. :}
Sorry for the delayed response in this thread ya’ll. I literally sat down and typed out a response 3 times only to get timed out once, accidentally hitting the back button on the mouse once and I can’t remember the 3rd.
Grrrrr….
In any case the reason for posting the picture was not for Daniela to ogle (although she has every right too) but because it’s demonstrates part of an ongoing study I am conducting on the adverse affects of contrast brilliance or more specifically, the various appearances of diamonds under diffuse lighting and what types or sets of proportions produce the most pleasing results.
If you’re interested, read on. If you’re not necessarily in the mood to exercise some brain cells skip this and go onto another thread cause this may be long. Cut geeks stick around cause this is kinda interesting. J
When speaking of contrast brilliance I am not referring to the observance of light return vs light leakage. Yes there is a contrast to be observed there but in the negative effect. Ie. more leakage contributes to less light return and a more dull looking diamond. So observing contrast between leakage and light return means there must be enough leakage within the diamond to be observed with the human eye and that is generally never a good thing. Perhaps small bits of leakage but not enough to observe large areas of it. The type of contrast that is the subject of this study is within diamonds that have extremely minimal to no leakage. Ie. the majority of the facets are functioning as mirrors/reflectors as opposed to windows/leakers concerning any light or reflections entering/exiting the diamond.
When these types of diamonds are observed in diffuse light conditions there is generally going to be the observance of 2 phenomena. Facets that are reflecting back white diffused light to the eye and facets that are reflecting back shadows or colors of the object in front of it or that are obstructing light. Gary has referred to this in another thread as “head obfuscation” (I know the spelling is right here Gary as MS Word didn’t give it the red underline).
So, in this study I have found there to be 2 adverse affects to contrast brilliance or “the brightness of the diamond in diffuse lights”.
One adverse affect is brought about by the steep/deep combos. For those not in the know, the steep/deep combo means that the diamond has pavilion angles that are coupled with a crown angle that is too steep and produces and undesired result in round brilliant cut diamonds. Some have heard me refer to this as the “ring of death” which means there is a large area of light leakage under the table that forms a large *ring*. That looks like this under LightScope or an IdealScope.
Weeding out the steep/deep combos are fairly easy with tools like the HCA (free and available online here), the BrillianceScope, the LightScope, and if you have a measuring device that can generate actual 3d models of diamonds that you can import into DiamCalc, that too. J
What is of note and probably the most critical aspect of these steep/deep combos is the pavilion angle specifically. For those who are running or who have ran HCA on certain diamonds you’ll note a sharp hit in the score as soon as the pavilion angles reach 41 degrees. Gary has done this for good reason because in many diamonds that are cut to get the AGS “0” score proportion rating, the factories who are trying to get the most yield from the rough try to preserve as much weight as possible and many times cut those pavilion angles steeper to help preserve this weight. What most of these factories don’t realize is that once you hit the transitional 41 degree mark, it adversely affects the brilliance of the diamond in a negative way, yet they attain that coveted AGS “0” score. Now … before I proceed, let me say that all diamonds with average pavilion angles of 41 degrees are NOT bad. Far from it. But what I am saying is that a lot of diamonds cut to ideal proportions can and do have sets of angles that contribute to a more dull stone and if those angles are at 41 degrees specifically (when coupled with crown angles approx. 34 degrees and higher, which many ideal cut stones have) if the majority of the pavilion main facets making up that 41 degrees are over 41 degrees then it will negatively impact the stone. If most are under 41 degrees then you’re ok. The only way to really know is with an optical exam of the diamond and critically examining the optical results. So the 41 degree pavilion angle presents a certain threshold within diamonds cut to ideal parameters.
Why am I bringing all this up? Because I’ve made another interesting discovery regarding another pivotal point in the world of pavilion angles. Duh… that sounded funny. (Try saying “pivotal point in the world of pavilion angles” 10x fast). Namely the 2nd adverse affect on contrast brilliance. The shallow/shallow combo. A note I have been making with diamonds as we test them in diffuse light conditions and also under the Isee2 which tests diamonds in diffuse lighting is different negative affects that are not caused by light leakage. How can this be? Is *too much* light return a bad thing?
Take the LightScope image of this diamond for example.
How about this one?
Each of these diamonds exhibit little to no leakage and both are taken under LightScope which shows, in great detail, light return vs leakage. So what could possibly be *negative* about this?
The answer is that it is NOT light return that is the problem but the balance of contrast between diffuse white light being returned to the eye vs facets reflecting back shadows/colors of the object in front of it.
The answer to this question can not be assessed using these technologies. HCA, red reflectors, and even the BrillianceScope cannot demonstrate this adverse affect demonstrated in the original picture I posted as these devices, more accurately reflect diamond appearance in direct lighting as opposed to diffuse lighting.
One reason I posted both of those stones in particular is because the one darker looking stone has pavilion angles that begin to approach the other end of the threshold … namely the 40.6 pavilion angle. It is at *this* juncture that I’ve been observing gradual decreases in overall brilliance under diffuse lights (and have demonstrated this via the photo). Interestingly, just about all responses were in agreement that the diamond on the right was the brighter stone. BTW … the diamond on the left (the darker stone under diffuse light) is THIS stone.
And has these proportions…
This diamond has pavilion angles that reach that pivotal point which can affect the diamonds appearance in diffuse light conditions. Remember … a highly reflective diamond with little to no light leakage, when observed in diffuse light conditions will reflect back either white diffuse light back to the observer or facets reflecting back shadows or colors of the object in front of it. If the contrast leans too heavy towards the darks rather than the lights there is an imbalance of contrast which negatively impacts the appearance of the diamond. The shallower the pavilion angles get the worse it impacts the appearance in those light conditions UNLESS it is compensated with proper crown angles of course.
So a 34.2/40.6 crown pavilion combo happens to work very well in direct light testing as observed in red reflectors. Here are the BrillianceScope results of the same stone.
Can’t argue with that. However diffuse light testing under Isee2 produces a 7.9 taking it’s primary hit in it’s scintillation reading. Another interesting example of this phenomena is with a diamond we had called in with a 34.6 crown angle & a 40.3 pavilion angle. That is the first LightScope image I posted.
This diamond has an even less attractive appearance in diffuse light conditions. Interestingly here are it’s Isee2 results.
So these have been my latest studies and I continue to research this as we get to inspect more varieties of AGS “0” diamonds. Interesting stuff eh?
Rhino
edited to make it clearer that its rhino's words and not mine.
It is him talking here not me. :}
Sorry for the delayed response in this thread ya’ll. I literally sat down and typed out a response 3 times only to get timed out once, accidentally hitting the back button on the mouse once and I can’t remember the 3rd.
Grrrrr….In any case the reason for posting the picture was not for Daniela to ogle (although she has every right too) but because it’s demonstrates part of an ongoing study I am conducting on the adverse affects of contrast brilliance or more specifically, the various appearances of diamonds under diffuse lighting and what types or sets of proportions produce the most pleasing results.
If you’re interested, read on. If you’re not necessarily in the mood to exercise some brain cells skip this and go onto another thread cause this may be long. Cut geeks stick around cause this is kinda interesting. J
When speaking of contrast brilliance I am not referring to the observance of light return vs light leakage. Yes there is a contrast to be observed there but in the negative effect. Ie. more leakage contributes to less light return and a more dull looking diamond. So observing contrast between leakage and light return means there must be enough leakage within the diamond to be observed with the human eye and that is generally never a good thing. Perhaps small bits of leakage but not enough to observe large areas of it. The type of contrast that is the subject of this study is within diamonds that have extremely minimal to no leakage. Ie. the majority of the facets are functioning as mirrors/reflectors as opposed to windows/leakers concerning any light or reflections entering/exiting the diamond.
When these types of diamonds are observed in diffuse light conditions there is generally going to be the observance of 2 phenomena. Facets that are reflecting back white diffused light to the eye and facets that are reflecting back shadows or colors of the object in front of it or that are obstructing light. Gary has referred to this in another thread as “head obfuscation” (I know the spelling is right here Gary as MS Word didn’t give it the red underline).
So, in this study I have found there to be 2 adverse affects to contrast brilliance or “the brightness of the diamond in diffuse lights”.
One adverse affect is brought about by the steep/deep combos. For those not in the know, the steep/deep combo means that the diamond has pavilion angles that are coupled with a crown angle that is too steep and produces and undesired result in round brilliant cut diamonds. Some have heard me refer to this as the “ring of death” which means there is a large area of light leakage under the table that forms a large *ring*. That looks like this under LightScope or an IdealScope.
Weeding out the steep/deep combos are fairly easy with tools like the HCA (free and available online here), the BrillianceScope, the LightScope, and if you have a measuring device that can generate actual 3d models of diamonds that you can import into DiamCalc, that too. J
What is of note and probably the most critical aspect of these steep/deep combos is the pavilion angle specifically. For those who are running or who have ran HCA on certain diamonds you’ll note a sharp hit in the score as soon as the pavilion angles reach 41 degrees. Gary has done this for good reason because in many diamonds that are cut to get the AGS “0” score proportion rating, the factories who are trying to get the most yield from the rough try to preserve as much weight as possible and many times cut those pavilion angles steeper to help preserve this weight. What most of these factories don’t realize is that once you hit the transitional 41 degree mark, it adversely affects the brilliance of the diamond in a negative way, yet they attain that coveted AGS “0” score. Now … before I proceed, let me say that all diamonds with average pavilion angles of 41 degrees are NOT bad. Far from it. But what I am saying is that a lot of diamonds cut to ideal proportions can and do have sets of angles that contribute to a more dull stone and if those angles are at 41 degrees specifically (when coupled with crown angles approx. 34 degrees and higher, which many ideal cut stones have) if the majority of the pavilion main facets making up that 41 degrees are over 41 degrees then it will negatively impact the stone. If most are under 41 degrees then you’re ok. The only way to really know is with an optical exam of the diamond and critically examining the optical results. So the 41 degree pavilion angle presents a certain threshold within diamonds cut to ideal parameters.
Why am I bringing all this up? Because I’ve made another interesting discovery regarding another pivotal point in the world of pavilion angles. Duh… that sounded funny. (Try saying “pivotal point in the world of pavilion angles” 10x fast). Namely the 2nd adverse affect on contrast brilliance. The shallow/shallow combo. A note I have been making with diamonds as we test them in diffuse light conditions and also under the Isee2 which tests diamonds in diffuse lighting is different negative affects that are not caused by light leakage. How can this be? Is *too much* light return a bad thing?
Take the LightScope image of this diamond for example.
How about this one?
Each of these diamonds exhibit little to no leakage and both are taken under LightScope which shows, in great detail, light return vs leakage. So what could possibly be *negative* about this?
The answer is that it is NOT light return that is the problem but the balance of contrast between diffuse white light being returned to the eye vs facets reflecting back shadows/colors of the object in front of it.
The answer to this question can not be assessed using these technologies. HCA, red reflectors, and even the BrillianceScope cannot demonstrate this adverse affect demonstrated in the original picture I posted as these devices, more accurately reflect diamond appearance in direct lighting as opposed to diffuse lighting.
One reason I posted both of those stones in particular is because the one darker looking stone has pavilion angles that begin to approach the other end of the threshold … namely the 40.6 pavilion angle. It is at *this* juncture that I’ve been observing gradual decreases in overall brilliance under diffuse lights (and have demonstrated this via the photo). Interestingly, just about all responses were in agreement that the diamond on the right was the brighter stone. BTW … the diamond on the left (the darker stone under diffuse light) is THIS stone.
And has these proportions…
This diamond has pavilion angles that reach that pivotal point which can affect the diamonds appearance in diffuse light conditions. Remember … a highly reflective diamond with little to no light leakage, when observed in diffuse light conditions will reflect back either white diffuse light back to the observer or facets reflecting back shadows or colors of the object in front of it. If the contrast leans too heavy towards the darks rather than the lights there is an imbalance of contrast which negatively impacts the appearance of the diamond. The shallower the pavilion angles get the worse it impacts the appearance in those light conditions UNLESS it is compensated with proper crown angles of course.
So a 34.2/40.6 crown pavilion combo happens to work very well in direct light testing as observed in red reflectors. Here are the BrillianceScope results of the same stone.
Can’t argue with that. However diffuse light testing under Isee2 produces a 7.9 taking it’s primary hit in it’s scintillation reading. Another interesting example of this phenomena is with a diamond we had called in with a 34.6 crown angle & a 40.3 pavilion angle. That is the first LightScope image I posted.
This diamond has an even less attractive appearance in diffuse light conditions. Interestingly here are it’s Isee2 results.
So these have been my latest studies and I continue to research this as we get to inspect more varieties of AGS “0” diamonds. Interesting stuff eh?
Rhino
edited to make it clearer that its rhino's words and not mine.
strmrdr
Super_Ideal_Rock
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So basically your trying to define the lower end of the sweet spot for optimal diamond performance as the high end is fairly well defined as high 34s and over 41.
The low end seems to affect the diffused lighting more than the direct light return from what your saying.
Im not sure I agree with some of your terminology,
“Facets that are reflecting back white diffused light to the eye and facets that are reflecting back shadows or colors of the object in front of it or that are obstructing light.”
Any reflective surface will reflect the color of an object in front of it so that has little to do with diamond angles.
Now due to light being split in the diamond some colors may be more prone to be returned, leaked or blocked at different points in the diamond.
As a further study colored lights should be used.
Im proposing that some of the dark areas instead of leaking light are splitting light in different colors/wavelengths and if one color/wavelength is more prevalent then those areas that it tends to send them too appear brighter while the areas that don’t work well with that wavelength appear darker.
When you shine white light thru a prism some of the colors will appear darker or lighter than others depending on how much of each color is making up the light source.
The same thing is true of diamonds.
This was demonstrated in my study of lasers we had a prism that was tuned to the wavelength of the laser beam.
Under white light it appeared to be a pretty bad prism simple because the wavelength it was tuned to was not very strong in the available lighting.
Hit it with a laser beam of the right wavelength and it acted as an almost perfect 90-degree light bender with min. lose and scatter compared to a prism that worked better under broad-spectrum lighting (white light).
Cutting a diamond to return a lot of all sections of the light spectrum is much harder than tuning it to return a large amount of a small portion of the light spectrum.
This is why most if not all diamonds have one particular light source they will look better under than others and it is different from one diamond to another.
An issue that has some bearing on this is the color of the diamond while it isn’t treated like a big deal color plays a part in light return.
It will affect how light is split up, absorbed or returned.
But I haven’t seen a study under various light sources to see how much and which colors affect the light return of a diamond.
It entirely possible that what is considered the best color is not the one that has the least effect on the light return under common light conditions.
This would explain some of the silence on this issue.
The low end seems to affect the diffused lighting more than the direct light return from what your saying.
Im not sure I agree with some of your terminology,
“Facets that are reflecting back white diffused light to the eye and facets that are reflecting back shadows or colors of the object in front of it or that are obstructing light.”
Any reflective surface will reflect the color of an object in front of it so that has little to do with diamond angles.
Now due to light being split in the diamond some colors may be more prone to be returned, leaked or blocked at different points in the diamond.
As a further study colored lights should be used.
Im proposing that some of the dark areas instead of leaking light are splitting light in different colors/wavelengths and if one color/wavelength is more prevalent then those areas that it tends to send them too appear brighter while the areas that don’t work well with that wavelength appear darker.
When you shine white light thru a prism some of the colors will appear darker or lighter than others depending on how much of each color is making up the light source.
The same thing is true of diamonds.
This was demonstrated in my study of lasers we had a prism that was tuned to the wavelength of the laser beam.
Under white light it appeared to be a pretty bad prism simple because the wavelength it was tuned to was not very strong in the available lighting.
Hit it with a laser beam of the right wavelength and it acted as an almost perfect 90-degree light bender with min. lose and scatter compared to a prism that worked better under broad-spectrum lighting (white light).
Cutting a diamond to return a lot of all sections of the light spectrum is much harder than tuning it to return a large amount of a small portion of the light spectrum.
This is why most if not all diamonds have one particular light source they will look better under than others and it is different from one diamond to another.
An issue that has some bearing on this is the color of the diamond while it isn’t treated like a big deal color plays a part in light return.
It will affect how light is split up, absorbed or returned.
But I haven’t seen a study under various light sources to see how much and which colors affect the light return of a diamond.
It entirely possible that what is considered the best color is not the one that has the least effect on the light return under common light conditions.
This would explain some of the silence on this issue.
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Well... yes to a point but primarily no.
Scroll down a tad for my commentary.
Kind regards,
Scroll down a tad for my commentary.
I appreciate your thougts strmrdr. It causes one to think more and use their noggin. The slight differences in color ... from D-F or from G-J or even to a K are so minute that I have not found color to impact internal reflection/refraction of light within diamond. At least not in the diamonds that typically go into engagement rings. Thanks for the feedback and your thoughts though.
Kind regards,
strmrdr
Super_Ideal_Rock
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hmmmmm maybe im missing something but I have a few more questions/comments
"Actually it does. When angles become to shallow it's not grabbing enough light from other angles and too much head obstruction becomes the problem causing the imbalance of contrast."
A diamond does not "grab" light it returns the light that enters it.
Are you talking about the outer facet acting as a mirror and returning the light from the surface instead of the light entering the diamond and being returned that way?
An example of this would be the left diamond in your original picture in the thread. The bright triangle is acting as a surface mirror instead of passing light into the diamond??
Im at work so I can’t do another picture but its the upper circled area on the left hand diamond in the modified picture I posted earlier.
"The stronger the light conditions the more the diamond will function as a prism"
So your saying that the brighter the light the more efficient the diamond is at returning light?
ok.... prove it
Light in vs light returned under different intensity lighting would be a very interesting graph.
But to be meaningful the wavelength of the light would have to be constant.
My thoughts are that the efficiency will stay fairly level but the overall level of light return isn’t strong enough to "wash out" the diamonds features making them more important in low intensity lighting.
That would give the appearance of it being less efficient.
I would think that wavelengths play a huge role in the difference.
Which brings me back too…
Is the wavelength of the light or the intensity that is causing the results you see in your study? :}
Real world there is a huge difference in the wavelengths of what is considered direct light and diffused lighting.
I think your study needs to address this issue.
Ps. Im assuming you are doing this study for presentation and not just for fun so am treating it like I would a professional evaluation in my field while keeping it friendly :}
"Actually it does. When angles become to shallow it's not grabbing enough light from other angles and too much head obstruction becomes the problem causing the imbalance of contrast."
A diamond does not "grab" light it returns the light that enters it.
Are you talking about the outer facet acting as a mirror and returning the light from the surface instead of the light entering the diamond and being returned that way?
An example of this would be the left diamond in your original picture in the thread. The bright triangle is acting as a surface mirror instead of passing light into the diamond??
Im at work so I can’t do another picture but its the upper circled area on the left hand diamond in the modified picture I posted earlier.
"The stronger the light conditions the more the diamond will function as a prism"
So your saying that the brighter the light the more efficient the diamond is at returning light?
ok.... prove it
Light in vs light returned under different intensity lighting would be a very interesting graph.
But to be meaningful the wavelength of the light would have to be constant.
My thoughts are that the efficiency will stay fairly level but the overall level of light return isn’t strong enough to "wash out" the diamonds features making them more important in low intensity lighting.
That would give the appearance of it being less efficient.
I would think that wavelengths play a huge role in the difference.
Which brings me back too…
Is the wavelength of the light or the intensity that is causing the results you see in your study? :}
Real world there is a huge difference in the wavelengths of what is considered direct light and diffused lighting.
I think your study needs to address this issue.
Ps. Im assuming you are doing this study for presentation and not just for fun so am treating it like I would a professional evaluation in my field while keeping it friendly :}
strmrdr
Super_Ideal_Rock
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Thinking about this brought me to a question.
If you take 2 diamonds that perform nearly the same on the b-scope (direct light) but one out performs the other on the isee2 (diffused light) will the one with the better isee2 score show a better heart pattern?
Also under diffused light how does the performance differ from 3 diamonds all with as close as possible the same pavilian angles but different crown angles?
only shallow, on in the middle, one steep but all within the ideal range.
If you take 2 diamonds that perform nearly the same on the b-scope (direct light) but one out performs the other on the isee2 (diffused light) will the one with the better isee2 score show a better heart pattern?
Also under diffused light how does the performance differ from 3 diamonds all with as close as possible the same pavilian angles but different crown angles?
only shallow, on in the middle, one steep but all within the ideal range.
strmrdr
Super_Ideal_Rock
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after thinking about this for a while I realized that we are likely talking about different things in my reply to your statement of
"The stronger the light conditions the more the diamond will function as a prism"
Instead of editing my original reply im leaving it up incase someone else is going that route of thinking.
Your not talking about efficiency at all but how the diamond appears to return light.
Your saying and the pictures prove this that under low light the large reflectors of the pavilion are if not removed from the equation their role is reduced and the diamond acts more like a series of mirrors than a prism.
This takes fire out of play.
The light level that the fire is eliminated is what seperates well cut from run of the cutters bench diamonds with the diamond that displays fire longer as the light is lowered and acts as a better mirror being the better cut diamond.
Hence my question about the hearts and the thought that the crown facet angles would have more of an effect than the pavilion facets in diffused lighting conditions.
Am I finally getting it??
I still am curious about the affects of wavelengths and how much it has to do with it however.
"The stronger the light conditions the more the diamond will function as a prism"
Instead of editing my original reply im leaving it up incase someone else is going that route of thinking.
Your not talking about efficiency at all but how the diamond appears to return light.
Your saying and the pictures prove this that under low light the large reflectors of the pavilion are if not removed from the equation their role is reduced and the diamond acts more like a series of mirrors than a prism.
This takes fire out of play.
The light level that the fire is eliminated is what seperates well cut from run of the cutters bench diamonds with the diamond that displays fire longer as the light is lowered and acts as a better mirror being the better cut diamond.
Hence my question about the hearts and the thought that the crown facet angles would have more of an effect than the pavilion facets in diffused lighting conditions.
Am I finally getting it??
I still am curious about the affects of wavelengths and how much it has to do with it however.
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Haha strm... love the questions.
Scroll on down senor.
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On 5/14/2004 2:34:43 PM strmrdr wrote:
hmmmmm maybe im missing something but I have a few more questions/comments
'Actually it does. When angles become to shallow it's not grabbing enough light from other angles and too much head obstruction becomes the problem causing the imbalance of contrast.'
A diamond does not 'grab' light it returns the light that enters it.
Right BUT if many angles are directed towards things that are obstructing light ... no light in = no light out. Shadows in = shadows out. Too many shadows and not enough light = poop contrast.
Are you talking about the outer facet acting as a mirror and returning the light from the surface instead of the light entering the diamond and being returned that way?
An example of this would be the left diamond in your original picture in the thread. The bright triangle is acting as a surface mirror instead of passing light into the diamond??
Good question. Very good question! That is an example of an *external* or *surface* reflection. This plays a part in the grand scheme of things but my focus has primarily been on *internal* reflections since external reflections are limited to light bouncing off the facet at certain (and very limited ) angles.
Im at work so I can’t do another picture but its the upper circled area on the left hand diamond in the modified picture I posted earlier.
We're on the same frequency.
'The stronger the light conditions the more the diamond will function as a prism'
So your saying that the brighter the light the more efficient the diamond is at returning light?
ok.... prove it
That would depend upon how you define *efficient*. Some people prefer the look of well cut diamonds under diffuse light some stronger light. I like em all as every light condition has another positive aspect to contribute in the beauty of the diamond!Weaker light conditions and you'll primarily see these issues of contrast. Stronger light conditions and you'll get bursts of fire. Here's what I'm talking about bossman. These pics are of 2 top of the line H&A stones. The pic on the left is taken in direct lighting (flash on specifically) and the 2nd in softer office lighting. In both pictures the diamond is reflecting back light to the observer. Obviously the pic on the left we can observe the phenomena of fire and dispersion while in the pic on the right the diamond is stripped of it's fire because the light source is not as intense.
Light in vs light returned under different intensity lighting would be a very interesting graph.
But to be meaningful the wavelength of the light would have to be constant.
My thoughts are that the efficiency will stay fairly level but the overall level of light return isn’t strong enough to 'wash out' the diamonds features making them more important in low intensity lighting.
That would give the appearance of it being less efficient.
I would think that wavelengths play a huge role in the difference.
Which brings me back too…
Is the wavelength of the light or the intensity that is causing the results you see in your study? :}
Yep. I think the contrasting pictures above answer your questions more easily than I can put it into words.
Real world there is a huge difference in the wavelengths of what is considered direct light and diffused lighting.
I think your study needs to address this issue.
Good point. Defining the light source and intensity is important. I'm working on capturing this phenomena on video too which will show what the light sources are and how the diamond appears under those various temperatures/intensities. A lil pet project I'm working on.
Ps. Im assuming you are doing this study for presentation and not just for fun so am treating it like I would a professional evaluation in my field while keeping it friendly :}
Which is why I appreciate the input.
Warm regards,
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----------------
On 5/14/2004 4:06:00 PM strmrdr wrote:
Thinking about this brought me to a question.
If you take 2 diamonds that perform nearly the same on the b-scope (direct light) but one out performs the other on the isee2 (diffused light) will the one with the better isee2 score show a better heart pattern?
Not necessarily. The Isee2 is performing it's exam in the face up position and what we perceive as the perfection of the hearts do not necessarily impact the score. ALTHOUGH if the symmetry, or better worded, "optical design" of the diamond is kaka this will impact the score. Put another way... when we look at the hearts we look at the continuity of them and the space between the heart and the cleft under it. When lower girdles reach a certain point (particularly when cut shorter) the clefts disappear and the stone would be rejected as a true H&A stone. The Isee2 is not looking for these things as the cleft and seperation between it and the heart ... it is just looking at the continuity and optical design of the gemstone in the face up position. With regards to it's symmetry score it is looking at the continuity (not just of the facets) but more specifically the continuity between the reflections within those facets. If the reflections form a perfect mirror image of their opposity corresponding facets the diamond is rewarded with the appropriate symmetry score. It is the only digital technology that rewards superior craftsmanship.
Also under diffused light how does the performance differ from 3 diamonds all with as close as possible the same pavilian angles but different crown angles?
only shallow, on in the middle, one steep but all within the ideal range.
You've just given me my *todo* when I get back up to the store.
Peace,
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Haha... I see you've been through a "digestion phase".
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On 5/15/2004 1:32:28 PM strmrdr wrote:
after thinking about this for a while I realized that we are likely talking about different things in my reply to your statement of
'The stronger the light conditions the more the diamond will function as a prism'
Instead of editing my original reply im leaving it up incase someone else is going that route of thinking.
Your not talking about efficiency at all but how the diamond appears to return light.
Exactly
Your saying and the pictures prove this that under low light the large reflectors of the pavilion are if not removed from the equation their role is reduced and the diamond acts more like a series of mirrors than a prism.
Yahtzee!
This takes fire out of play.
The light level that the fire is eliminated is what seperates well cut from run of the cutters bench diamonds with the diamond that displays fire longer as the light is lowered and acts as a better mirror being the better cut diamond.
You're hired.
Hence my question about the hearts and the thought that the crown facet angles would have more of an effect than the pavilion facets in diffused lighting conditions.
Am I finally getting it??
Yep.Except if you take note in the pics I posted there are no external reflections in the diffuse light pic except one off the upper girdle facet around the 12:30 position. HOWEVER I purposely blocked external reflections in that pic (I think there was only one other off a star facet) to demonstrate. You got it bro.
I still am curious about the affects of wavelengths and how much it has to do with it however.
That would be interesting to know too but I do not know how to measure the intensity of wavelengths.
Thanks so much for your thought provoking questions and input. If anyone was following the line of thought you originally had hopefully this will answer and address those questions/issues.
Kind regards,
strmrdr
Super_Ideal_Rock
- Joined
- Nov 1, 2003
- Messages
- 23,295
Im thinking that looking at as 2 phases direct light and diffused light is too wide a swing if you look at the last 2 pictures you posted compared to the first in this thread there are clearly 3 different things going on.
Here is an experment for you to test the wavelenth theary,
Take a white table/arm type lamp and put a ge reveal 40w light bulb in it and put it on a dimmer about 2 feet above the diamond.
Set the vid. camera on a tripod pointing down towards the top of the diamond.
The tricky part will be positioning the camera and the light because idealy they wwould be in the same place directly above the diamond.
Take a video of the diamond while moving the dimmer slowly from full on to off.
repeat with a peice of white papaer between the diamond and the light.
Then put a florecent light in place of the lamp and take a comparison shot.
Iv found that on a dimmer the ge reveal light bulbs suffer from less wavelenth shift than reg. lightbulbs plus they are less yellow tinted than most bulbs.
edit to add make a scale around the dimmer 1-10 and pause as the pointer on the switch hits each number.
This gives you a reference when comparing the with paper and without videos.
edit again: even better would be to use a photographers light meter to set the light level the same with and without the paper between the diamond and the light source and compare the shots.
This would give an answer if its the intensity or the difusion that makes a difference.
Here is an experment for you to test the wavelenth theary,
Take a white table/arm type lamp and put a ge reveal 40w light bulb in it and put it on a dimmer about 2 feet above the diamond.
Set the vid. camera on a tripod pointing down towards the top of the diamond.
The tricky part will be positioning the camera and the light because idealy they wwould be in the same place directly above the diamond.
Take a video of the diamond while moving the dimmer slowly from full on to off.
repeat with a peice of white papaer between the diamond and the light.
Then put a florecent light in place of the lamp and take a comparison shot.
Iv found that on a dimmer the ge reveal light bulbs suffer from less wavelenth shift than reg. lightbulbs plus they are less yellow tinted than most bulbs.
edit to add make a scale around the dimmer 1-10 and pause as the pointer on the switch hits each number.
This gives you a reference when comparing the with paper and without videos.
edit again: even better would be to use a photographers light meter to set the light level the same with and without the paper between the diamond and the light source and compare the shots.
This would give an answer if its the intensity or the difusion that makes a difference.
strmrdr
Super_Ideal_Rock
- Joined
- Nov 1, 2003
- Messages
- 23,295
This composite picture shows what I was talking about.
a - acting as a prism with full fire with the pavilian replectors kicked in full
b. acting as a deep faceted mirror with some internel returrn from the pavilian facets.
c - acting as a shallow mirror with a faceted top with the pavilian taken out of the equation other then the depth of the diamond affecting the degree of return. With the shollower parts acting as better surface mirrors with the exception of the very center which is still getting some internel return.
But the orange dot (which i assume is a camera led tape it off next time:}) doesnt show much signs of being distorted like it would be if it was a deep return leading me to believe that that area may just be acting as a good shallow mirror better than some of the surrounding areas.
But I think overall that area is a combination of surface and some internal return.
The better cut the diamond the longer it should look like a vs looking like b and the longer it should look like b vs looking like c as the light level decreases?
Rhino what say you ?:}
a - acting as a prism with full fire with the pavilian replectors kicked in full
b. acting as a deep faceted mirror with some internel returrn from the pavilian facets.
c - acting as a shallow mirror with a faceted top with the pavilian taken out of the equation other then the depth of the diamond affecting the degree of return. With the shollower parts acting as better surface mirrors with the exception of the very center which is still getting some internel return.
But the orange dot (which i assume is a camera led tape it off next time:}) doesnt show much signs of being distorted like it would be if it was a deep return leading me to believe that that area may just be acting as a good shallow mirror better than some of the surrounding areas.
But I think overall that area is a combination of surface and some internal return.
The better cut the diamond the longer it should look like a vs looking like b and the longer it should look like b vs looking like c as the light level decreases?
Rhino what say you ?:}
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