ASET versus IdealScope, when you cant have both

[RichDD]

I''m going in tomorrow to look at some more diamonds from a different local vendor. I''m letting them try to win me over from a better diamond I could get online. Most of what they carry is GIA cert''d, and he''s picking out the Ex/Ex/Ex ones to look at. I know GIA is a bit looser than AGS with grading, but I''m getting the angles and percentages to check out with HCA.

Apart from the numbers on the report, I think the only other thing they''ll have is the ASET. I''m almost sure they dont have an idealscope. Can''t I tell the same info from the ASET as with an IS? I mean, apart from the fact that it''s a pain to use, wont it let me know the same info for a round brilliant? And with the ASET, what is the difference between the red,pink, and orangish shades. Which is better?

Thanks guys (and gals)!

 

[jstarfireb]

I believe an ASET and IS are basically equivalent for looking at round stones. Basically, here's the breakdown of how they compare (someone correct me if I messed up!):

IS / ASET / meaning

red / red / strong light return
pink / green / less strong light return
black / blue / obstruction
white / black / leakage

For fancy cuts like princesses, ASET is much more helpful than IS.

 

[RichDD]

But how does one interpret the orange and pinks on the ASET? I''ve used one before and you see a wide mix of colors beyond straight red/blue/green

 

[strmrdr]

Date: 10/2/2008 8:27:12 PM
Author: RichDD
But how does one interpret the orange and pinks on the ASET? I've used one before and you see a wide mix of colors beyond straight red/blue/green

With more colors in the scope you will see more mixing of the colors.
Go with the dominate color as that will be the primary light return source for that area.
The mix will also depend of if you use black or white behind the diamond.

For example with ASET-White Pink is a mix of strong light return and a little leakage.

here is the basic mix when they are mixed equal strength:
RED and GREEN MAKE YELLOW
BLUE and RED MAKE PURPLE
BLUE and GREEN MAKE BLUE-GREEN OR AQUA
RED, BLUE and GREEN MAKE WHITE

But beyond that you have this color mixing chart.

http://en.wikipedia.org/wiki/RGB_color_model

"To see how different RGB components combine together, here is a selected repertoire of colors and their respective relative intensities for each of the red, green, and blue components:"

As you can see orange is a mix of red and green with the red being brighter.
That would mean that that area of the diamond is primarily drawing light from the red zone of the scope with a secondary draw from the green part of the scope.

Pink can either be light red or red mixed with white or even red mixed with blue or even red mixed with blue mixed with green.

 

[Garry H (Cut Nut)]

ASET is better than IS but harder to interpret.
ASET is essential for fancy shapes. You will be fine

 

[John P]

Okay Strm, you're scaring me. That post reminded me of someone else who can get crazy-technical.

Nice info and graphic.

Rich, I'd add a couple of thoughts: First, it helps to have a closed environment like a darkroom with even lighting for observation if that is possible. Second, be sure of positioning; keep the girdle flush with bottom of the colored cone and be sure there is no tilt for most accurate results. Even a slight shift can cause color mixing.

Many of the professional ideal-scope and ASET photos you see on PS are done in a darkroom with a fixed setup and controlled lighting approaching 5000K for IS and a bit softer for ASET. Alternately, when you’re in a normally lit room using a handheld unit there's typically far more ambient light. This can make the rich reds and blacks you see in the professional IS photos appear more pink and grey. It's similar with the handheld ASET.

It’s also worth noting that diamonds with top light return and superior optical symmetry will have more crisply separated colors. Since many of the images posted on PS are quite well cut we can become accustomed to seeing a "typical" IS or ASET footprint in a diamond here. Diamonds in the mainstream can have quite different appearances.