Comparing Firescope images

[avalpert]

Can people comment on a comparison of these firescope images. I know there are more issues to consider but I want to look at each individually.

 

[avalpert]

2

 

[avalpert]

3

 

[avalpert]

4

 

[Maxine]

Date: 6/21/2005 7:39:56 PM
Author: avalpert
3

I have a question (???).........why did you label #3 "this is a pain?"...just curious!!?

 

[avalpert]

I had trouble uploading the file since names using th enumber wouldn't work, it was just my frustration with the uploading process.

 

[Rhino]

Each of these images are what would be considered first generation red reflector images, akin to FireScope however it appears these are not quite *Firescope* shots but more like Idealscope shots.

The first bit of information to be garnered from these is whether facets are functioning as either mirrors or windows. Red/blacks = mirrors, white = windows.

So clue #1 tells us that each of the stones you have posted demonstrates that the majority of the facets are indeed functioning as mirrors. (good!).

Secondly each of the diamonds are displaying a superior optical symmetry pattern. That too is good.

Blacks are indicative of 2 things. 1. Areas of contrast primarily seen in the head on position (obscuration) and 2. Areas of very intense light return when rocked slightly (not obscured). Some diamonds have more of this and some less, particularly between the arrow shafts/heads. The presence of *more* generally = greater scintillation.

The limitations of these images are thus.

Red reflectors are not the best indicators of the shallow/shallow combo's so it is virtually impossible for a layman to weed out those duds based on red reflector images (1st or 2nd generation, and HCA scores for that matter). They are however excellent in seperating the steep/deep combos.

First generation red reflectors are also not accurate indicators of *intensity* of light return as most reds appear to be of the same saturation. That is the primary difference between 1st and 2nd gen rr's which also show the details resulting in facet yaw. It is possible to note the very weak areas of light return in the last image where the reds are very pale around the perimeter (upper girdle region) similar to 8* or ACA NL.

Once I complete an exhaustive tutorial we're working on for princess cuts we're going to be editing our tutorial on the red reflectors to include not only the strengths (and how to properly interpret these images) but also this tools weakness and limitations which many are not aware of. Ie. there are many stones which will have seemingly GREAT red reflector images that will definitely not make the future GIA Grade 1's or AGS "0"s for that matter and for good reason.