Why the special names for painting or digging?

[kenny]

Correct me if I'm wrong, but painting and digging is deciding the angle at which certain facets are cut for a certain purpose.

HELLO!
ALL facets are cut at various angles for various purposes.

So why these two special names (not to mention all this drama) for what has been named painting and digging?

Is it simply the departure from some tradition?

 

[diagem]

Date: 5/25/2006 7:31:42 AM
Author:kenny
Correct me if I''m wrong, but painting and digging is deciding the angle at which certain facets are cut for a certain purpose.

HELLO!
ALL facets are cut at various angles for various purposes.

So why these two special names (not to mention all this drama) for what has been named painting and digging?

Is it simply the departure from some tradition?

I hope i can explain it in the easiest fashion.

Its not a departure from tradition....

The term comes from the brillianteering (the final stage of the polishing process)of the pavilons mainly on fancy colored diamonds...

its a term used to differentiate the facet angle range on facets that are positioned one next to the other. the lower the degree range between each facet is considered "painting", the higher the degree range between facets is considered "digging".

I hope i made it clear enough for you to understand...

 

[Garry H (Cut Nut)]

there are 8 main facets on the crown and pavilion.
These are at 360 degrees divided by 8 = 45 degree positions.
Then the minor facets can be applied to split these facets - on the pavilion there are 2 between the mains - 11.25 degrees, 22.5 between the lower girdles and then 11.25 to the next main.

On the crown side the upper girdles are in the same position - the little facets that seperate the main facets and the girdle.
Above them and joining the mains and the table are little star factes - the split the upper girdles - so between the 8 mains there is 11.25 to the first upper girdle - then 11.25 to the star facet, then another 11.25 to the next upper girdle then 11.25 to the next main.

Date: 5/25/2006 7:31:42 AM
Author:kenny
Correct me if I''m wrong but painting and digging is changing the angle at which certain facets are cut for a certain purpose.

HELLO!
ALL facets are cut at various angles for various purposes.

So why these two special names (not to mention all this baggage) for what has been named painting and digging?

This provides for a good amount of contrast as these facets gather light from very different directions from the surrounding room etc.

But if those 11.25 compass points (azimuths) are pointed in directions closer to the mains - that is called painting - it reduces the contrast and makes the crown or pavilion minor or girdle facets shallower which can reduce leakage and contrast - the facets get shallower.

Digging is when the facets are pointed away from the mains - and then the facet angles become steeper = more lekage and more contrast.

Of course you can paint the lower and dig the upper.

the best measure of these adjustments is the compass point or azimuth - the direction the facet faces as measured relative to the 11.25 degrees.
10.25 = -1 degree painting
12.25 = +1 degree digging

GIA have not worked out a measurement system yet - it appears they assume their graders can look and guess the dgree of painting and digging - it remains to be seen how accurate their new scanner is and if it can measure this effect.

Helium wins hands down at present - and GIA bought one a couple of years ago - so I guess they have a standard to live up to.

 

[kenny]

Yes DiaGem, that is very clear.

But still painting and digging (P&D) is just all about determining the angles of certain facets.

So what if P&D fall another name (brillianteering) or if it happens at the end of the process.

Again, it is just setting the angles of some facets for some purpose, just like the rest of the process.


Let me put it another way.
Take a diamond (cut for optical performance as opposed for weight retention) with no painting or digging.
Every facet on that stone was set at some angle for some optical purpose.

So again, why the special terms painting and digging?

 

[Paul-Antwerp]

If you want to know about cutting terms, you always have to go back to Dutch, or actually to the local Flemish dialect of Antwerp or the Kempen-area, just outside of Antwerp.

Digging as such is a good translation of ''scheppen'', the act using a shovel.
Painting is a bad translation of ''plekken'' (dialect) or ''plakken'' (Dutch). In the Kempen-area, plekken is the act of applying plaster to a newly built wall, so that you can paint it later on, or apply wallpaper on it. In the city of Antwerp, the same term means something entirely different, here it is the act of putting wall-paper on the wall. In both cases however, it is clear that one tries to follow the same angle as the brick-wall itself.

''Plekken'' and ''scheppen'' are classical tricks used by cutters for ages, in order to adjust previous errors in cutting, or to hide a surface blemish, or a remaining natural. There are dozens of reasons to ''paint'' or ''dig'' a facet.

If you look at the stone from the top, you can consider the stone as a circle of 360°. Each facet has a specific location on this circle. When a facet is painted or dug, it means that the cutter has gone away from this specific location. In the case of digging, this means that this facet will dig deaper into the girdle. In the case of painting, it means that there will be less difference in angle with the adjoining facet, thus it is being ''plekked'' to the next facet, at almost the same angle.

Hope this clarifies,

 

[Garry H (Cut Nut)]

Date: 5/25/2006 7:53:31 AM
Author: kenny
Yes DiaGem, that is very clear.

But still painting and digging (P&D) is just all about determining the angles of certain facets.

So what if P&D fall another name (brillianteering) or if it happens at the end of the process.

Again, it is just setting the angles of some facets for some purpose, just like the rest of the process.


Let me put it another way.
Take a diamond (cut for optical performance as opposed for weight retention) with no painting or digging.
Every facet on that stone was set at some angle for some optical purpose.

So again, why the special terms painting and digging?

Painting and digging lower and raise the facets respectively - that is a by product.
The purpose is often but not always weight retention.

If a diamond is a little deep then painting can improve its performance

if a little shllow then digging can potentially help the light performance

 

[diagem]

Date: 5/25/2006 8:05:16 AM
Author: Garry H (Cut Nut)

Date: 5/25/2006 7:53:31 AM
Author: kenny
Yes DiaGem, that is very clear.

But still painting and digging (P&D) is just all about determining the angles of certain facets.

So what if P&D fall another name (brillianteering) or if it happens at the end of the process.

Again, it is just setting the angles of some facets for some purpose, just like the rest of the process.


Let me put it another way.
Take a diamond (cut for optical performance as opposed for weight retention) with no painting or digging.
Every facet on that stone was set at some angle for some optical purpose.

So again, why the special terms painting and digging?

Painting and digging lower and raise the facets respectively - that is a by product.
The purpose is often but not always weight retention.

If a diamond is a little deep then painting can improve its performance

if a little shllow then digging can potentially help the light performance
But it can allways make a thick or very thick girdle plane look thin and admirable...

 

[Garry H (Cut Nut)]

only in America DG because for some really wierd reason you guys measured girdles at the thin valley.

The rest of the world, and now AGS, measure girdle thickness at the thickest mains and upper gridle junctions.

 

[diagem]

Date: 5/25/2006 8:18:52 AM
Author: Garry H (Cut Nut)
only in America DG because for some really wierd reason you guys measured girdles at the thin valley.

The rest of the world, and now AGS, measure girdle thickness at the thickest mains and upper gridle junctions.

Agreed, see that the second time...

but it still will make any Thick to Very thick girdle look (visuall) more aesthetic to the un-profesional eye...

right?

PS. i understand that you are assuming i am from the US...,