Evaluating an Emerald Cut diamond for light play from 360° vids

[Emrldlvr]

I understand when evaluating an EC stone for light play in 360° videos you want to avoid stones with large dark areas like this
BUT would a dark zone like the one below be problematic for good light play?

3.03-Carat Emerald Cut Diamond | Blue Nile

www.bluenile.com

Also, is this the same phenomenon as the bow-tie effect that I see in my current EC in certain light settings, or something different?

@Karl_K you were very helpful in assisting me to parse our some of these issues in a previous post of mine a while back. Any insights?

 

[Karl_K]

What lighting is the ring in?

Yes it can look like that.
The second one could be ok.
Those videos are like viewing the diamond at 4 inches.

 

[Emrldlvr]

What lighting is the ring in?

Yes it can look like that.
The second one could be ok.
Those videos are like viewing the diamond at 4 inches.

Sunlight. I can’t remember if it happens when the sun is behind me or when it is behind the ring.

 

[Garry H (Cut Nut)]

The sun is shining from higher up but on the diamond. It appears to be fluorescent.
Never look at diamonds in direct sunlight to judge cut.
It appears to have the bowtie effect of being very dark because the lens is seeing the lens *which is dark)

 

[Garry H (Cut Nut)]

“EEK, My diamond goes dark or blue in sunlight”

If you look at a diamond in direct sunlight then better the cut - the better the light return, the darker the diamond will appear. And it may also look dark blue.

I did a small study today, Christmas Eve 2019 on a hot 30C cloudless day in front of the store.

The first photo shows 5 different cut styles with direct sunlight coming over my right shoulder. You will note the ideal-cut round has a lot of black in it. But mostly it is blue – The same blue that appears in some parts of the lower left white cushion and the lower heart shape. There is little or no blue in the other stones.



In this image where I have moved the stones into the shade of my body you can see how bright all of the diamonds are. If people want to look at diamonds out doors this is how it should be done – or better still, under a diamond tree with hundreds of point light sources which will enhance the fire.


People jump to the conclusion that the blue colour in sunlight is from the fluorescence. WRONG! The strongest fluorescence is in one of the cushions and the marquise. Fluoro has nothing to do with how the diamonds appear in daylight (other than improving their colour).



Note: the direct sunlight photo again below - the ideal-cut round diamond is showing blue from the sky and dark because the light from the sun is only lighting up a few facets. Even though the sun is big, it is a very small point light source, about the same as a single small halogen or LED in a very high ceiling.
The other fancy shapes all have crushed ice effects and are glowing with various reflected light bouncing all around in the stones. (note my marquises do not have bow ties hahaha).




Hope this helps in the rare cases where people get worried

 

[Matthews1127]

Evaluation of EC’s begins with video. Performance of a virtual stone is more complicated, and requires more visual aid to properly evaluate a fancy cut stone.
You will want ASET/IS images.
You will also want to see the stone in video while in different lighting environments and in different backgrounds to judge performance.
Finally, you’ll want to make sure you have a comfortable return window, so once you receive the diamond, you can evaluate it up close and personal....and in all of your every day environments.

 

[Ceilimom]

“EEK, My diamond goes dark or blue in sunlight”

If you look at a diamond in direct sunlight then better the cut - the better the light return, the darker the diamond will appear. And it may also look dark blue.

I did a small study today, Christmas Eve 2019 on a hot 30C cloudless day in front of the store.

The first photo shows 5 different cut styles with direct sunlight coming over my right shoulder. You will note the ideal-cut round has a lot of black in it. But mostly it is blue – The same blue that appears in some parts of the lower left white cushion and the lower heart shape. There is little or no blue in the other stones.



In this image where I have moved the stones into the shade of my body you can see how bright all of the diamonds are. If people want to look at diamonds out doors this is how it should be done – or better still, under a diamond tree with hundreds of point light sources which will enhance the fire.


People jump to the conclusion that the blue colour in sunlight is from the fluorescence. WRONG! The strongest fluorescence is in one of the cushions and the marquise. Fluoro has nothing to do with how the diamonds appear in daylight (other than improving their colour).



Note: the direct sunlight photo again below - the ideal-cut round diamond is showing blue from the sky and dark because the light from the sun is only lighting up a few facets. Even though the sun is big, it is a very small point light source, about the same as a single small halogen or LED in a very high ceiling.
The other fancy shapes all have crushed ice effects and are glowing with various reflected light bouncing all around in the stones. (note my marquises do not have bow ties hahaha).




Hope this helps in the rare cases where people get worried

Garry H how would you expect an (AGS)Ideal cut MRB to show inside with just chandelier lighting with no outside light impacting the room? Would the diamond still look dark? I really appreciate your differing diamond examples and the explanations.

 

[Garry H (Cut Nut)]

Garry H how would you expect an (AGS)Ideal cut MRB to show inside with just chandelier lighting with no outside light impacting the room? Would the diamond still look dark? I really appreciate your differing diamond examples and the explanations.

Hi C, The going dark only happens when there is a very small - very strong - single point light source.
A nicely cut Round will show one two or 3 very blinding bright flashes making your eye over expose and the surrounding facets appear dark and dead.
A chandelier will create many small flashes as there are many light sources.
Bets ever is adiamond tree - a million point light sources shining thru the spaces between leaves. Works best on a cloudy day.

 

[Karl_K]

Garry H how would you expect an (AGS)Ideal cut MRB to show inside with just chandelier lighting with no outside light impacting the room? Would the diamond still look dark? I really appreciate your differing diamond examples and the explanations.

static any diamond can look kinda meh in just chandelier lighting with no outside light impacting the room remember the diamond is not seeing the light you are primarily it is seeing light from behind you. There are a lot of dark zones in that lighting.

Now stand so those lights are behind you and move the diamond around.........even a shiny spoon would be impressive.

 

[Garry H (Cut Nut)]

static any diamond can look kinda meh remember the diamond is not seeing the light you are primarily it is seeing light from behind you.
Now stand so those lights are behind you (SO THE DIAMOND IS IN THE SHADE) and move the diamond around.........

i ADDED THIS SO THE DIAMOND IS IN THE SHADE - i ASSUME YOU MEANT THAT kARL.
yES.
A diamond is an optical device of windows and mirrors for redirecting your line of sight.
The brightest diamonds redirect with the least internal bouncing around - so very few flashes.
Th emarquise shows a gazzilion small flashes in direct sunlight because the rays bounce about and get split and multiplied.

 

[Karl_K]

Garry I clarified my response.
Hope it is more clear now.
chandelier lighting creates a ton of dark zones on the walls and ceilings.

 

[Garry H (Cut Nut)]

Garry I clarified my response.
Hope it is more clear now.
chandelier lighting creates a ton of dark zones on the walls and ceilings.

The back of a shiny spoon is the best way (Sergey taught me) to identify light sources. It also indicates the color temperature.

 

[Ceilimom]

Karl_K and Garry H if the diamond looked bleh inside at night with the chandelier and outside in direct sunlight it just looked dark greyish, is there some other factor that I should be aware of that causes this appearance? The blues seen in your MBR example ring is very pretty by the way. What color grade was this diamond?

 

[Garry H (Cut Nut)]

Karl_K and Garry H if the diamond looked bleh inside at night with the chandelier and outside in direct sunlight it just looked dark greyish, is there some other factor that I should be aware of that causes this appearance? The blues seen in your MBR example ring is very pretty by the way. What color grade was this diamond?

Cant remeber the grade but in that size all my stock is G-D.
The blue is 90% the sky ble and maybe 10% paler blue from fluoro.