Ideal-Scope Reference Chart for Your Review and Criticsm

[Garry H (Cut Nut)]

We have been asked by many people and some labs to produce an informative, but easy to use reference guide for the ideal-scope.

Before we put this on the website I would like to run it past Rocky Talky people for comments and constructive criticism.

Once it is finalized we will be happy to give anyone and everyone 300dpi print quality download files or whatever.

I have a little space at the bottom for a few comments - maybe how to use the scope or whatever. Please make suggestions.

We have been working on this for a very long time (it has been distilled down from a very complex array).

Please offer your opinions.

Regards

Garry Holloway (Cut nut)
Christian Pike

 

[valeria101]

Hi!

this is quite inspiting!

One thing I would add: a column to the left with the efect of cut characteristics (perhaps commonly understood defects rather than technical and not widely understood parameters)which place a piece towards the extremes of your idealscope ranges. Then, maybe a description of the ideal thing (in visual terms and in terms of what should a customer care and ask about) on top, as conclusion of the analitic exercise. Calling the first range 'symmetry' does tempt the reader to look for other such clues below... I would say that the best use of such a chart is to relate it directly to the combination of stats one would get about the cut of a stone.

Well, I guess this while pic would help even someone who hasn't seen a diamond in his life. In the perfect world, such a sheet should exist for all those trendy cuts out there and in each jewelry store!

Ok, you are getting close to converting me to cut standards and away from my prefered realm of rose and table cuts and whatever-cut colored stones...

 

[aljdewey]

Very nice work, Garry. I think it's definitely helpful.....can be hard as an amateur to know exactly what you're "seeing" when you look. This gives a basis for comparison.

I'll definitely be printing it in it's final incarnation.

 

[Hest88]

This is great, Garry! Are you doing to do the same with fancies as well?

 

[Richard Sherwood]

Excellent. Very helpful. I've been trying to put together the same thing to incorporate in my appraisals, with no luck so far. This solves the problem.

Is it okay if I include this page in my appraisals, Garry?

 

[dimonbob]

Thanks Garry,
Is this your Birthday present to us?? This is very nicely done and very helpful. It is also simple enough for a novice to understand.
Great work!

 

[Giangi]

Very well done, Garry! It truly is helpful!

 

[Mara]

I concur...this chart is excellent and will show many a newbie what to look for. There are so many small nuances when looking at the IS images, whether in print/online form or under the scope itself that a chart like this enables one to study the differences between a/b/c/d and really see for themselves what they should be looking for. What appeals to them.

Great job Garry!

 

[Garry H (Cut Nut)]

No worries Rich - we will make it freely available in good quality images.
Please look hard and criticise it - i am sure we have not thought of everything yet.

 

[shurikt]

Nice work!

My only suggestion would be to include more images! For example, Light Return: Poor and Ideal-Scope View: Deep are the same image. Also Symmetry: Excellent, Light Return: Excellent and Ideal-Scope View: Ideal are all the same image. I'm sure you would agree that more than only one stone would qualify for these categories...

I'd also love to see the difference between 'tweaked' and non-tweaked stones. By the way, I hate that term because it is incredibly vague. Can somebody come up with one that more accurately reflects what 'tweaked' is?

 

[smaggard]

Garry or Richard or anyone;

What does the "contrast" portion refer to? I never see that in the glossary for the IS and stuff.
Is this just referring to the balance between brilliance, fire, and scintillation?
Or is contrast some aspect of the diamond I'm missing?
Maybe it's called something else at times?
thanks

 

[Garry H (Cut Nut)]

A chess board has contrast.

 

[smaggard]

----------------
On 9/12/2003 5

7:53 PM Cut Nut wrote:

A chess board has contrast.
----------------

So is contrast basically that there is an even distribution of color, whether it be pink, red, black, all the way around in any given area?
So under the table directly, ideally should all be the same color etc.?


I guess I'm wondering what the middle image under contrast represnts? An Ideal contrast??

 

[Richard Sherwood]

Maybe a section that deals with the "cheated girdle" issue?

You could show the IdealScope image, and then show a profile view of a diamond with a cheated girdle versus non-cheated girdle.

 

[Colored Gemstone Nut]

Hey Garry,

Did you publish your article about cheated girdles you were working on??? I remember awhile back you were writing an article that had yet been published. I'll take a browse on your site...

-Josh

 

[Mikesgirl]

This chart is really helpful and informative. The info on this site and on the box seemed inadequate - this is a great aid.

 

[Rhino]

The issue of contrast brilliance/scintillation plays a major role in the Isee2 grade.

The depth of contrast and amount of it are 2 of the determining factors in the overall grade of the stone.

Here is an example of illuminating the checkerboard of the diamond.

Peace,
Rhino

 

[Rhino]

Here is an interesting comparison of checkerboards showing graphically Gary's point about contrast. I'm currently working on an updated tutorial on this very subject and how the Isee2 integrates with this type of analysis. Neat stuff.

Rhino

 

[smaggard]

Thanks Rhino....that makes sense now.

 

[Garry H (Cut Nut)]

----------------
On 9/12/2003 8:30:25 AM valeria101 wrote:

Hi!

this is quite inspiting!

One thing I would add: a column to the left with the efect of cut characteristics (perhaps commonly understood defects rather than technical and not widely understood parameters)which place a piece towards the extremes of your idealscope ranges. Then, maybe a description of the ideal thing (in visual terms and in terms of what should a customer care and ask about) on top, as conclusion of the analitic exercise.
GH.....Please give me a better idea of what you want Valeria?

Calling the first range 'symmetry' does tempt the reader to look for other such clues below...

GH...We like the idea of introducing the ideal-Scope to the traditional trained folk in the trade who believe that symmetry equals proportions, otherwise we are asking them to dump all their previous beliefs I would say that the best use of such a chart is to relate it directly to the combination of stats one would get about the cut of a stone.
gH There is an enormous range of proportions that have nice ideal-scope results. It is too confusing to list those extremities, maybe in a few years after GIA introduce 25 degree crown angle diamonds to cutters, then people might be happy to know the proportion combinations that make nice stones.

Well, I guess this while pic would help even someone who hasn't seen a diamond in his life. In the perfect world, such a sheet should exist for all those trendy cuts out there and in each jewelry store!

GH.... We would add fancy cuts later. First things first


Ok, you are getting close to converting me to cut standards and away from my prefered realm of rose and table cuts and whatever-cut colored stones...

----------------

 

[Garry H (Cut Nut)]

----------------
On 9/12/2003 4

3:57 PM shurikt wrote:

Nice work!

My only suggestion would be to include more images! For example, Light Return: Poor and Ideal-Scope View: Deep are the same image. Also Symmetry: Excellent, Light Return: Excellent and Ideal-Scope View: Ideal are all the same image. I'm sure you would agree that more than only one stone would qualify for these categories...

I'd also love to see the difference between 'tweaked' and non-tweaked stones. By the way, I hate that term because it is incredibly vague. Can somebody come up with one that more accurately reflects what 'tweaked' is?
----------------

thanks Shurikt.
We debated using the same or different images, and for various reasons choose to use some of the same ones (not because of a shortage of examples).

No point pointing out tweaking - even though some are there. No one in the real world knows about this stuff yet!

 

[Garry H (Cut Nut)]

----------------
On 9/12/2003 5:17:33 PM smaggard wrote:

----------------
On 9/12/2003 5

7:53 PM Cut Nut wrote:

A chess board has contrast.
----------------

So is contrast basically that there is an even distribution of color, whether it be pink, red, black, all the way around in any given area?
So under the table directly, ideally should all be the same color etc.?


I guess I'm wondering what the middle image under contrast represnts? An Ideal contrast??


----------------

There are 2 primary causes of contrast Smaggard.
Here is the answer to the first case:

One is the darkness one sees that represents our head obscuring light sources - in diffuse lighting this means you will see a dark star in a symmetrical stone.
The Ideal-scope (and other red feflector scopes) mimics that by creating a star from the light that has come from the lens and returned to the viewer through the lens.
The stones on the left and on the right in rows 3 and 4 (shallow and deep) have too much darkness poorly distributed throughout the stone.
Longer length of the lower girdle facets and larger sized tables can cause the stars to get skinny - like in the lower right. These stones can have higher light return (remeber any darkness = no light return, contrary to what some have said). But increased light return is not neccessarily increased brilliance!
The 3 stones in the middle bottom row would have pleasing balance of brilliance and fire - but this is a personal issue.
Remember too that the fire you see comes off those darker areas of a diamond. Even though the very shallow stone has a shallow crown angle - it can display very good fire - crazy isn't it.

 

[Garry H (Cut Nut)]

The second type of contrast comes about from leakage.
This is very common in fancy cuts and less well proportioned rounds.

Take the deep stone in rows 3 and 4 as an example.

The "no go zone" or "ring of death" just inside the table in this very leaky stone will appear dark when the diamond is set because no light can get in from behind.

An interesting aside, this stone is similar in proportions to one that Brad and Jan used as an example of how HCA did not work. The thread that resulted from it was why I was booted of Diamond Talk.

If you are not careful you can be impressed by these stones when sold loose, because they allow light that enters the pavilion to escape out the crown as very strong fire from the dull and darker leakage areas. Be sure you examine loose stones with no possibility of light getting in the pavilion.

Now if you do own one of these stones, then set it as high as possible, in as open backed a setting as practical and clean it every day in ammonia and detergent and hot water, and you will have a very firey diamond.

The ideal format for contrast is a well balanced star. If the stone is too shallow then the whole stone will look too dark, and if it is way too deep then the center will be dark and the outside will be very dull because of leakage.
The star fades a bit when the stone is just a little too deep.

Now take a princess cut for example.
They show very little head shadow.
Much of the darkness or contrast comes from leakage.
AGS wrote a paper showing a (red and blue) illuminated type Firescope / ideal-scope principle with no back lighting at all. To try this, take your ideal-scope and look at a fancy cut in a closed back setting with no backlight, or better still, a loose gem in a black box. you must have strong light illuminating the outside of your ideal-scope. You will see something like this picture on the left.
Note that the contrast from the leakage is not as marked as that from the head shadow dark areas in the normal ideal-scope view.
So you see it is possible for leakage to provide contrast and therefore scintillation (when the stone is rocked from side to side). In this very well cut princess, the leakage patches are well enough spread out to be attractive.
In the first case - our diamond with a leaky table - the conrast is not nicely spaced and causes patchy scintillation.

Any questions?
This is hard to explain.

 

[Iiro]

Hi Garry,

Sorry for not resposing to your email. I had ( still have) major computer problems.

I lost all, over 2000, emails at one second, yours included. Not good.

Iiro