Mapping Idealscope and ASET results

[bschai]

Hi,

I understand the idea behind idealscope and ASET .

But I have two questions:

1. Is there a good way to compare one stone''s idealscope to another''s ASET results?


Do I just compare the using the following mapping:

IS: Black ASET: BLUE
IS: Red ASET: Red
IS: PINK ASET: Green
IS: Pale Pink ASET: ?
IS: white ASET: Black

But How do I translate the different shades of red into ASET terms?



2. Also, is more IS:black area(or ASET: BLUE) better or worse? (i.e. is having more direct light reflection better) I.e. even though it''s total internal reflection back to you, but if you look at it directly, you will be blocking the light, so effective more IS:black (or ASET:BLUE) area means the diamond will appear darker?


Thanks.

bschai

 

[Garry H (Cut Nut)]

Since AGS decided not to use ASET with back light it is not easily possible to attempt what you bare trying to do.

 

[Lord Summerisle]

so in an ASET image

Blue, Green & Red = good

Black = leakage = bad ?

 

[strmrdr]

Date: 8/24/2007 3:37:51 AM
Author: Lord Summerisle
so in an ASET image

Blue, Green & Red = good

Black = leakage = bad ?

black or white can == leakage depending on if back-lighting was used.
leakage isn't bad in the right place and the right amount depending on the shape/cut of the stone.

blue is 30 degrees obstruction(head shadow)
red is return from high angle sources. (diamond face up: overhead lighting)
green is return from lower angle sources. (diamond face up: table lamps, and reflections from walls)

Green and blue and white/black also provide contrast for contrast brilliance (basically a light spot looks brighter next to a dim spot than by itself)
A diamond with an all red ASET would be boring and lifeless.

 

[Rhino]

Hi bschai,

Good advice given here. To see ASET imagery best bet is to either

a. Have an actual photograph of it under ASET OR
b. Have a model generated that is loaded into the Gem Advisor software.

In answer to your questions specifically ...

Do I just compare the using the following mapping:

IS: Black ASET: BLUE

Generally yes, however the black generally seen in red reflectors is usually a bit less than 30 degrees obstruction.

IS: Red ASET: Red

Not necessarily. There are instances where red in IS = Green in ASET.

IS: PINK ASET: Green

Not necessarily here either. Light pinks in red reflectors can translate to dark/bright reds in ASET.

IS: Pale Pink ASET: ?

Same as above.

IS: white ASET: Black

Not always. Sometimes there are instances where I''ve seen white in red reflectors translate to green in ASET (albeit darker greens becuase it is mixed with the black behind it). IMHO the ASET is not the best tool for observing leakage because it is not backlit. Backlit reflectors show leakage much better and more critically. The ASET I personally use is backlit for this purpose.

But How do I translate the different shades of red into ASET terms?

As suggested here, not a good idea to attempt it.


2. Also, is more IS:black area(or ASET: BLUE) better or worse? (i.e. is having more direct light reflection better) I.e. even though it''s total internal reflection back to you, but if you look at it directly, you will be blocking the light, so effective more IS:black (or ASET:BLUE) area means the diamond will appear darker?

Yes. If there is too much black/blue, especially if that spills over into the lower halves (and not the mains only) you''re generally going to see too much obstruction/darkness, particularly in diffuse light conditions. (See attached image below.) Stones like that will generally take a hit in the AGS system because of an imbalance of contrast with an emphasis on too much obstruction/darkness. I have examples of these phenomena if interested.

Hope that helps.

 

[JohnQuixote]

ASET’s main advantage is that it defines what areas of light return are intense (red) and what areas are less intense (green).This has more implications in fancy shapes than in rounds, but it’s useful to see in both.

A backlit ideal-scope image is best for showing overall light return and leakage. ASET, often not backlit, is a more refined breakdown of angular spectrum. Another reason it's useful to have both.

Here’s a visual aid I hope is helpful... It's from this past thread that has more detail and discussion, if you’re interested.