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Color Description System, Grading System


#1

When I set up my site, one problem I knew I would encounter was
describing gem colors and grades. The only useful color description
systems I could find were either extremely complex scientific; or
proprietary and not readily avalable to the public.

So I developed my own.

Then I added a grading system.

They are fully explained (I think;>) on various pages of my site

I know neither system is perfect and I’m looking for quality input
that will make them more useful. I do claim a copyright on both, but
anyone can copy and distribute the systems; so long as the
distribution is complete, unmodified, and references my website.
If/as improved versions are developed they will be numbered and
freely available.

I think everyone know sthe value of a system that allows one to
communicate more accurately.

Thanks and regards from Thailand, Dave Webster www.asia-gems.com

End of forwarded message


#2

In almost every other industry there is a standard color grading
system called “Pantone”. It is used for paints, inks, printing and
garments for sure and probably everywhere else except the jewelery
industry. The color chips are too readily available and too cheap to
be used in the jewelery industry.

cutter12


#3

Your color grading system looks nearly identical to the system used
by GIA. The main difference is that they use a written modifier and
capitalization for the hue, i.e., slightly bluish Green (sl. bG) vs.
bluish Green (str. bG) and you use a + and - sign Slightly Bluish
Green (-BG) vs. Strongly Bluish Green (+BG).

The one hue description I did not see in your system is a 50/50 split
of hues, Blue Green/Green Blue. In this hue combination, neither
color is the dominant like in the hue bluish green, where green is
dominant.

Why not use the GIA system? It seems similar enough plus more
flexibility with the hue description. The tone and saturation
descriptions are nearly identical (1,2,3 etc.)


#4

cutter12 mentioned Pantone colors…

I work with Pantone colors quite a bit these days, communicating with
people in different time zones about color decisions for print and
electronic display.

But does the gem industry really need such a specialized, exacting
color system?

Even GIA’s system has been criticized as too cumbersome. (I personally
don’t think it is, but then I’m GIA trained.)

Kat Tanaka actually in the midst of designing color grading documents
for Tahitian pearls.


#5

Your color grading system looks nearly identical to the system used
by GIA. The main difference is that they use a written modifier and
capitalization for the hue, i.e., slightly bluish Green (sl. bG) vs.
bluish Green (str. bG) and you use a + and - sign Slightly Bluish
Green (-BG) vs. Strongly Bluish Green (+BG).

But my CDS also reveals saturation and tone. The GIA system uses
separate tables for saturation and tone.

The one hue description I did not see in your system is a 50/50 split
of hues, Blue Green/Green Blue. In this hue combination, neither
color is the dominant like in the hue bluish green, where green is
dominant.

I haven’t been around enough to see an absolutely 50/50 split. What
gems would it apply to?

Why not use the GIA system?

As I said in my original e-mail. GIA has copyrighted their system
and does not distribute their system freely. If I use it I would be
violating their copyright.

   It seems similar enough plus more flexibility with the hue
description.  The tone and saturation descriptions are nearly
identical (1,2,3 etc.)  

Again, its a matter of “free usage,” and I personally feel that 5
divisions are difficult enough to segregate. AIGS uses 6 on tone and
saturation.

Also, although I have never seen a GIA handbook on color stone
grading, I have never heard mention that GIA uses percentage of
brilliance in grading. IMHO, color is first, brilliancy (internal
luster) is second. Brialliancy flashes tell a lot. That is where
you actually see the hue and saturation. Brilliancy % and “quality
of brilliance” (i.e. clean or fuzzy) will also tell you a lot about
"make" and inclusions.

Also, as I stated, my CDS aqnd grading system aren’t carved in
granite.

Thanks for your evaluation. I appreciate your comments.

Dave Webster
www.asia-gems.com