New Article by Brian Pollard Compares ASET and Ideal-Scope

[Diamond_Hawk]

I have been following this discussion with interest. Glad to hear how it worked out. Congratulations on finding a diamond that you love!

 

[Venzen007]

I have a question about something that was said in the OP article regarding what the ASET colors mean, and I've seen it put this way many times.

"Green – Reflected light, not as intense as (red) direct light and of lower quality, representing the light return from the horizon to 45 degrees."

As I understand it, yes, green represents the sections of the stone which are returning light coming into the stone 0 to 45 degrees, where the 0 degree plane is parallel to the the plane of the viewer's eye (typically, for ASETs, that's also parallel to the stone's table). However, I don't see how green automatically means that light will be less intense and/or of lower quality. Isn't that dependent on the light source, its intensity and positional relationship to the stone?

IF that's the correct understanding, then the explanation for green should include a disclaimer or explicitly clarify its working assumptions, because I think, as it is, it can be misleading. Only when the diamond is directly facing the strongest source of light will it be true that green represents those sections of the stone that will reflect less intense light because the stone isn't getting intense light from the 0 to 45 degree direction, but that doesn't mean that it couldn't. If the only light in the room is coming from 30 degrees, I'd expect those areas that show green on an ASET to be the most intense, while the areas that show red on an ASET to be less.

As for quality of light reflection, doesn't that have more to do with the color saturation of the green or red rather than that the area is green or red?

(Sorry, @Karl_K , but I'll likely forever tag you in anything remotely close to a technical question!)

 

[Karl_K]

I have a question about something that was said in the OP article regarding what the ASET colors mean, and I've seen it put this way many times.

"Green – Reflected light, not as intense as (red) direct light and of lower quality, representing the light return from the horizon to 45 degrees."

As I understand it, yes, green represents the sections of the stone which are returning light coming into the stone 0 to 45 degrees, where the 0 degree plane is parallel to the the plane of the viewer's eye (typically, for ASETs, that's also parallel to the stone's table). However, I don't see how green automatically means that light will be less intense and/or of lower quality. Isn't that dependent on the light source, its intensity and positional relationship to the stone?

The angles are referenced from the stones girdle midpoint.
There are a ton of lighting conditions that the brightest light is in the green zone.
Most living rooms for example.
But it is not all bad people will just move their hand to catch the light if they aren't happy with how it looks.
If you consider I just want to l9ook at it anytime and its giving me a show then green zone light return has to be considered.
Which is why ASET can be used to design diamond that are badly performing in the real world.

 

[Karl_K]

As for quality of light reflection, doesn't that have more to do with the color saturation of the green or red rather than that the area is green or red?

(Sorry, @Karl_K , but I'll likely forever tag you in anything remotely close to a technical question!)

ASET does not show intensity just direction.

Tag me anytime this stuff is fun!

 

[Venzen007]

The angles are referenced from the stones girdle midpoint.

Thanks for that clarification.

ASET does not show intensity just direction.

I don't meant light source intensity, but reflective intensity of the stone. I'm looking for something to account for the pinks to reds and the light greens to emerald green, etc.

Tag me anytime this stuff is fun!

Yay!

 

[Karl_K]

Thanks for that clarification.



I don't meant light source intensity, but reflective intensity of the stone. I'm looking for something to account for the pinks to reds and the light greens to emerald green, etc.



Yay!

Color mixing caused by areas of the diamond having multiple light paths.
Here are some images from past discussions.
1st is back light only, 2nd ASET, third ASET with the red turned black.

 

[Venzen007]

Wouldn't light-path color (blue, green, red) "mixing" give you purples, yellow-browns, more blues, blue greens, etc.? What I notice in ASETs are gradients of a single color, which I'd assumed meant lesser reflectivity in those areas, or basically color mixing with white (leakage), so that in those areas with light green or pink, those areas are lined up to reflect red (or green), but are only reflecting them back partially due to varying degrees of leakage.

EDIT: Like in an Idealscope, despite only having a single main color to reflect, you have bright reds to light pinks. I'd think that color gradient speaks to the strength of the light return in those areas (the amount reflected vs. the amount leaked), not the strength of the light itself coming into the diamond.

 

[Karl_K]

Wouldn't light-path color (blue, green, red) "mixing" give you purples, yellow-browns, more blues, blue greens, etc.? What I notice in ASETs are gradients of a single color, which I'd assumed meant lesser reflectivity in those areas, or basically color mixing with white (leakage), so that in those areas with light green or pink, those areas are lined up to reflect red (or green), but are only reflecting them back partially due to varying degrees of leakage.

Light leakage of less than ~2% which is in every MRB is enough to lighten the color in ASET white.
When the back light is over bright it gives a false indication of leakage.
Anything that is not lighter than the lightest part in the center circle is not meaningful leakage in IS/ASET

Also every vendor does post processing some in camera and some afterwards that can create some differences.

 

[Venzen007]

So, in an ASET, what is going on, specifically, so that some greens and reds are washed out to pink or very light green while others are solid green, solid red? And if you've already answered, forgive me; I haven't understood.

 

[Karl_K]

So, in an ASET, what is going on, specifically, so that some greens and reds are washed out to pink or very light green while others are solid green, solid red? And if you've already answered, forgive me; I haven't understood.

minor leakage present in every MRB which can be made worse by over bright back lights.

 

[Venzen007]

Speaking generally, then, for all shapes, a lighter red or light green in comparison to the robust reds and greens, is indicative of some slight leakage, likely imperceptible to the unaided eye, made more apparent by strong backlighting?

Wouldn't this mean those those sections of lighter, washed out color just aren't set up to be as reflective as those sections of more saturated color, allowing some of the backlighting to sneak through? Is it more a matter of the limitations of the material rather than design?

 

[Karl_K]

Speaking generally, then, for all shapes, a lighter red or light green in comparison to the robust reds and greens, is indicative of some slight leakage, likely imperceptible to the unaided eye, made more apparent by strong backlighting?

Wouldn't this mean those those sections of lighter, washed out color just aren't set up to be as reflective as those sections of more saturated color, allowing some of the backlighting to sneak through? Is it more a matter of the limitations of the material rather than design?

Its complex.
Every area of a diamond has multiple light paths ASET just shows the dominate one with modification from the others.
A light path from the pavilion of the stone is seeing much higher intensity light than the reflected light from the scope.
This makes minor leakage more apparent and if gets worse with over bright back lights.
Then there is no such thing as perfect reflectors some of the light passes through and some is absorbed by the diamond.

 

[Karl_K]

ASET white vs ASET black

 

[Venzen007]

So, to restate to be sure I got it, the intensity of light coming in through the pavilion is, in some cases, overpowering the reflective quality of the material and coming through anyway, mixing with the less intense light reflected off the ASET cone that is reflected off the same section of the diamond that is getting blasted from the "back" with the backlight?

 

[Karl_K]

To understand this you need to know about virtual facets:
https://www.pricescope.com/articles/virtual-facets-and-patterns-discussion-about-step-cuts
The article did not go into multiple light paths: A virtual facet can draw light from the pavilion, the green zone and the red zone in ASET all at the same time.
Here are the major virtual facets in a mrb of this specific make, they change with different proportion sets but they are generally similar, there are thousands more that are smaller and can come to play in bright direct lighting. I never got around to finishing the series, to much resistance because it disagreed with some things AGS was preaching. I was right but it was not worth the fight.
Anyway......ASET blends multiple virtual facets into one blob of color, it has low resolution in showing virtual facets.

 

[Venzen007]

Thanks, @Karl_K . I'll read it!

 

[Venzen007]

In the bigger yellow circle, we have light pink and a more saturated pink. Is the difference there due to one virtual facet returning light more or better than the other? Same with the greens in the bottom yellow circle? Or, is it something about that virtual facet is mixing with the backlight coming in from the pavilion?

 

[Karl_K]

Or, is it something about that virtual facet is mixing with the backlight coming in from the pavilion?

Correct.
It could and probably is just as bright as any of the other areas of darker tone viewed from the front without back light.
They have one light path from the red/green zones and a weak one from the pavilion most likely on the other side of the pavilion. Because the back light has a higher brightness we know that the secondary light path is very weak.

 

[Karl_K]

Given that a forward light path is the same as a reverse light path(physics) what color will the area be the light ray is hitting(arrow) in ASET?

 

[Venzen007]

I can't make out the meaning of the various %s, but roughly measuring that angle, I'd think the color of that area where the arrow is pointing would be red, reflecting light entering from that 70ish degree angle; meanwhile, the other end of that path would show blue, reflecting light entering from from close to 0 degrees.

I had a thought while thinking about this.

Has anyone every thought or tried to construct a self-lit ASET, where the outside of the ASET would not allow in light, but internally, the ASET cone would emit (adjustable) light consistent with the three color bands on a normal ASET scope? Adjustable, so we could experiment with altering the intensity of single color paths, or turning them off all together.

 

[flyingpig]

I had a thought while thinking about this.
Has anyone every thought or tried to construct a self-lit ASET, where the outside of the ASET would not allow in light, but internally, the ASET cone would emit (adjustable) light consistent with the three color bands on a normal ASET scope? Adjustable, so we could experiment with altering the intensity of single color paths, or turning them off all together.

I see many issues with this.
First, it would be extremely difficult and expensive to build a self-lit ASET that outputs even brightness throughout.
Second, I am not an expert in physics and optics. But, it is possible that red, blue, green may interfere with each other inside the self-lit ASET. This may or may not be what you want. Mix red, blue and green = white?? and perhaps purple, yellow and light blue in certain areas? I don't know. It would be very interesting to see.
Third, in most cases, diamonds reflect reflected light. The current ASET design is a better representative of what happens IRL than the self-lit ASET.

 

[Venzen007]

The design, I'd think, would work just like the current ASET design, it would just be changing the first main bounce location into the light source itself. So, if the red, blue, green don't interfere in the current ASET design, I don't see why they would in my thought experiment design.

As far as it being extremely difficult and expensive, I don't see that there's any reason to think that, and I disagree that the backlight ASET design is a better representation of IRL viewing, since rarely, if ever, are our diamonds lit so brightly (or hardly at all) from the back.

 

[Karl_K]

Calibrating a self light scope would be a nightmare and would not be affordable for people to buy and use.
I dont think it would tell us anything that the one we have now would. It just doesn't have high enough resolution and never will.

 

[Venzen007]

I agree it would cost more than the current ASET, but maybe not cost prohibitive for everyone.

When you say "calibrating", what do you mean? I'd think matching the angles and color proportions of the interior cone to those of the current ASET's interior cone would be easy. The engineering would just be from the interior wall of the cone out, where the lighting would be housed. A thick enough colored section of material with uniform diode placements to illuminate it doesn't seem difficult in theory.

I just wonder whether such a device would still give us the various color gradients of our individuals colors or whether the colors reflected would be more standard, red, blue, green. Plus, what would happen if you turned off the Red and left on the Green, or vice versa; I just think those results would be interesting to see and then explain, but maybe all that stuff has already been worked out some other way.

 

[Karl_K]

I can't make out the meaning of the various %s, but roughly measuring that angle, I'd think the color of that area where the arrow is pointing would be red, reflecting light entering from that 70ish degree angle; meanwhile, the other end of that path would show blue, reflecting light entering from from close to 0 degrees.

% of the light beam.
It has a strong red, multiple weak blues and a 2 weak whites and a weak green.
But the white are a much higher intensity so they would be amplified.
Overall it would be red with a hint of dilution from the white, the blue is also modifying it somewhat.
Since it is a very tiny spot it would be hidden in a larger red area.
What is important is understanding that exact spot on the diamond has multiple light paths.

 

[Karl_K]

I agree it would cost more than the current ASET, but maybe not cost prohibitive for everyone.

When you say "calibrating", what do you mean? I'd think matching the angles and color proportions of the interior cone to those of the current ASET's interior cone would be easy. The engineering would just be from the interior wall of the cone out, where the lighting would be housed. A thick enough colored section of material with uniform diode placements to illuminate it doesn't seem difficult in theory.

I just wonder whether such a device would still give us the various color gradients of our individuals colors or whether the colors reflected would be more standard, red, blue, green. Plus, what would happen if you turned off the Red and left on the Green, or vice versa; I just think those results would be interesting to see and then explain, but maybe all that stuff has already been worked out some other way.

Intensity of each light zone would have to be calibrated to get useful results.
That is what is hard.

 

[Venzen007]

Maybe someone is up for it! (but not me). lol

 

[Karl_K]

Keep in mind the physical ASET scope is just a visual tool for showing people to AGS, AGS bases it score on a virtual computer generated ray tracing based on scan data.

 

[Venzen007]

But I can't play with that stuff.

 

[Venzen007]

How do you scan a diamond, anyway? I have laser scanners and commercial-grade photogrammetry software, but even glass gives that stuff difficulties.