Fire and dispersion techy help please?

[adamasgem]

Fire is, to me, the ability of the stone to separate pure spectral hues such that they are easily resolved by the viewer. This, of course. is environment dependent.

Virtual facets tend to make the areas of pure spectral hues smaller, and thus less resolvable by the viewer.

Hi Marty,
I just did some experiments.
There appears to be less very bright fire seen from main facets - most of the activity comes from the upper girdle facets when (Master Stones 7 and 12) are viewed from about 25cm in LBox with X 5 degrees and Y 3 degrees of rotation.
The viewing environment is one that slightly exaggerates fire with thin slits of light from 5 fluoro tubes with a dark ceiling.

I examined several LBox movies (as they palyed as well as the individual photo jpegs) and it seems from the camera distance of about 20cm that my observations are well supported.
From 60cm away it is harder to resolve where the fire is coming from, but it seems to be more balanced between table and crown facets.

Garry..

The "Fire" in the mains is split into a minimum of three plus parts, the area of the arrow head, and the areas on each side of the arrowhead on the mains, which are usually split colors.

The rest of the diamond have smaller areas of distinct fire.

The largest single relative area of "fire" I remember seeing,next to the aroow heads, when rotating a highly symmetrical stone, and observing the color change, comes from the arrow shafts, each shaft having different colors. This observation is consistent with what one sees in a dual color contrast device, like a hearts and arrow viewer, firescope, etc.

Your envirionment is different then mine, (5 versus 10000 "points") so you may have some aliasing effects, just as GIA's metric based on single ray area and angle of incidence chromatic flares, would conceivably have, at least in my considered opinion.

Mathematically what you "see" in a reverse ray trace is aliased by the number of interactions you limit yourself to.

I have deconvolved some of the pictures I have taken into the spectrum elements observed a long time ago which were not as good as I would have liked to have, but will examine them again when I take the new set on my masters after the holidays.

 

[Garry H (Cut Nut)]

Fire is, to me, the ability of the stone to separate pure spectral hues such that they are easily resolved by the viewer. This, of course. is environment dependent.

Virtual facets tend to make the areas of pure spectral hues smaller, and thus less resolvable by the viewer.

Hi Marty,
I just did some experiments.
There appears to be less very bright fire seen from main facets - most of the activity comes from the upper girdle facets when (Master Stones 7 and 12) are viewed from about 25cm in LBox with X 5 degrees and Y 3 degrees of rotation.
The viewing environment is one that slightly exaggerates fire with thin slits of light from 5 fluoro tubes with a dark ceiling.

I examined several LBox movies (as they palyed as well as the individual photo jpegs) and it seems from the camera distance of about 20cm that my observations are well supported.
From 60cm away it is harder to resolve where the fire is coming from, but it seems to be more balanced between table and crown facets.

Garry..

The "Fire" in the mains is split into a minimum of three plus parts, the area of the arrow head, and the areas on each side of the arrowhead on the mains, which are usually split colors.

The rest of the diamond have smaller areas of distinct fire.

The largest single relative area of "fire" I remember seeing,next to the aroow heads, when rotating a highly symmetrical stone, and observing the color change, comes from the arrow shafts, each shaft having different colors. This observation is consistent with what one sees in a dual color contrast device, like a hearts and arrow viewer, firescope, etc.

Your envirionment is different then mine, (5 versus 10000 "points") so you may have some aliasing effects, just as GIA's metric based on single ray area and angle of incidence chromatic flares, would conceivably have, at least in my considered opinion.

Mathematically what you "see" in a reverse ray trace is aliased by the number of interactions you limit yourself to.

I have deconvolved some of the pictures I have taken into the spectrum elements observed a long time ago which were not as good as I would have liked to have, but will examine them again when I take the new set on my masters after the holidays.

Marty the strongest fire was either side of the arrow heads.
The with me (or the camera staionary and 5 strip lights and the stone movement covers lights from pretty well the entire blue and red regions of an ASET.
Can your system adequately show the relative intensity or returns?
Also I have 2 eyes

 

[Serg]

Diamond in Ring, Zero painting, DC531

 

[Serg]

Diamond in Ring, 5 degree crown painting ( Fire bigger )

 

[Serg]

Loose diamonds, zero painting

 

[Serg]

Loose diamond, 5 degree crown painting( Fire less)
for what conditions have we to optimize and grade cut?

 

[Serg]

.

 

[beryl]

Sergey:
. Early Christmas present for you at new thread 'Concave Facets'.

 

[adamasgem]

Marty the strongest fire was either side of the arrow heads.
Can't really comment on the relative stength of the areas around the mains, only the relative areas of single colors, the greater the area of pure color the easier seen, I believe

The with me (or the camera staionary and 5 strip lights and the stone movement covers lights from pretty well the entire blue and red regions of an ASET.

Still an aliasing envirionment, assymetric

Can your system adequately show the relative intensity or returns?

I imagine a photo can be analysed as to the relative strength in localized areas, as I do for the entire stone


Also I have 2 eyes
Doesn't mean that "fire" can't be seen with monocular vision

 

[adamasgem]

Loose diamonds, zero painting

Serg... I don't understand your rendering scale. What do the areas of red (numerical 7.5) mean.
These are dead zones, areas of no light return, on a non painted stone, are they not ??????
Could you please explain.

 

[beryl]

Marty:
. What means 'aliasing environment'? I only graduated from a 'cow college' ("MooU"), where we were told that "The object of language is to communicate." (Paul Bagwell)

 

[adamasgem]

Marty:
. What means 'aliasing environment'? I only graduated from a 'cow college' ("MooU"), where we were told that "The object of language is to communicate." (Paul Bagwell)

Sorry MooU, I been using the terminology so long, I didn't realize some didn't understand what I was trying to communicate. By aliasing envirionment, I mean one that has such a limited scope that it is easy to satisfy optimization criteria.

For example, GIA's fire metric is based ONLY on chromatic flares from a parallel wavefront hitting the table (circular area, I believe) perpendicularly, an unrealistically simple lighting condition one would never find in nature. Some might say that my 10,000+ points of light would never be found, but it is a condition where one CAN SAY, was not tailored to fit a specific stone.

It is one where similar conditions, if not more limited, could easily be found in nature, and is optimal for observing fire.

I attempted to model one with a uniform multiple directionality of light sources, one that was relatively immune from the effects of various normally sized stones, and that was somewhat optimal to show the "fire" producing ability of a stone, via a direct picture. One that was NOT easy to optimize a stone to fit a "metric".

I believe a relative metric could be derived from an analysis of the stone's picture(s) and its' resultant hues and strengths produced from the white light source. When I say pictures, I mean that even with the multiplicity of sources, the facets will light up different colors when the stone is rotated slightly, but the overall pictures will be consistent in quality of "fire" observed for a particular stone.

Sloppy cuts will be readily discernable.

 

[beryl]

Marty:
. What means 'aliasing environment'? I only graduated from a 'cow college' ("MooU"), where we were told that "The object of language is to communicate." (Paul Bagwell)

Sorry MooU, I been using the terminology so long, I didn't realize some didn't understand what I was trying to communicate. By aliasing envirionment, I mean one that has such a limited scope that it is easy to satisfy optimization criteria.

. I don't understand the explanation either. Moo.

 

[beryl]

Marty called me by phone and I finally sifted out that 'aliasing environment' means 'garbage in'.

 

[Serg]

re:Serg... I don't understand your rendering scale. What do the areas of red (numerical 7.5) mean.
These are dead zones, areas of no light return, on a non painted stone, are they not ??????

Marty ,

metric is very simple : (Dispersion angle)*Intensity ( we account only full spectrum beams only yet. if spectrum had been split , value is zero( we will fix it latter)

So red is best zones, dark is zero Fire( due either zero intensity or zero dispersion )

 

[adamasgem]

re:Serg... I don't understand your rendering scale. What do the areas of red (numerical 7.5) mean.
These are dead zones, areas of no light return, on a non painted stone, are they not ??????

Marty ,

metric is very simple : (Dispersion angle)*Intensity ( we account only full spectrum beams only yet. if spectrum had been split , value is zero( we will fix it latter)

So red is best zones, dark is zero Fire( due either zero intensity or zero dispersion )

Serg.. That is what is confusing to me.

The red areas (high fire) in your fire diagram of the unpainted diamond are normally areas of NO LIGHT RETURN (dark) in a face up view, if I remember right.

 

[Garry H (Cut Nut)]

re:Serg... I don't understand your rendering scale. What do the areas of red (numerical 7.5) mean.
These are dead zones, areas of no light return, on a non painted stone, are they not ??????

Marty ,

metric is very simple : (Dispersion angle)*Intensity ( we account only full spectrum beams only yet. if spectrum had been split , value is zero( we will fix it latter)

So red is best zones, dark is zero Fire( due either zero intensity or zero dispersion )

Serg.. That is what is confusing to me.

The red areas (high fire) in your fire diagram of the unpainted diamond are normally areas of NO LIGHT RETURN (dark) in a face up view, if I remember right.

Marty if you take the default inpainted stone you can check fire for a 'loose diamond' or take the "Diamond in ring' option in which latter case, the outer vee shapes go dark.
If you paint the stone then you get yellow zones.

 

[Serg]

reerg.. That is what is confusing to me.

The red areas (high fire) in your fire diagram of the unpainted diamond are normally areas of NO LIGHT RETURN (dark) in a face up view, if I remember right.

--

Marty,

for unpainted diamond I published two diagrams. these VF's are black in "Diamond in ring" diagram and red in "Loose diamond" diagram

 

[beryl]

.. The attached illustration was in error. The concept is correct - that a given beam is dispersed more by exiting at the greater of the two interface angles. The specific data are wrong; the RI range of tourmaline is not dispersivity; it is birefringence = the difference in RI of a single ray in various directions through the crystal.
.. I noticed this as I was about to send it to a colored-stone person, who might have seen the error.