Why your diamond goes dark or blue in direct sunlight

[Starfacet]

Great read! I also want to say that the marquise ring at the beginning of the thread is !!

 

[John P]

So: When you took the game inside you removed the majority of brightness in the hemisphere. You still had that very bright source, but it occupied only 1/2 a degree of space. You "turned off" much of the rest. The diamond was looking for light everywhere, and still finding the sun, but not the ambient light it had everywhere else, outside. Well-cut diamonds give back what they receive.

Physiological: Outside the brightness made your pupils constrict. When you went inside they adapted to the darker environment by dilating, to allow you to see more detail in the dark. This why we wait for our eyes to adjust, so we don't trip over furniture, etc. Once you went inside you started seeing the environmental details I have explained more clearly. Cameras adjust for brightness and darkness in a similar way, but without nearly the depth or sophistication of the human eye.

Per the above, I tracked down a post with some images.
https://www.pricescope.com/communit...l-cut-diamonds-revisited.150108/#post-2722281

 

[the_mother_thing]

@John Pollard Thank you for the explanation; I get the gist of it, even though I probably will need to re-read it a couple times to mentally digest it.

 

[diamondsR4eVR]

So last night we did family bowling. Lots of fun! But I noticed my SF RB is dark inside the bowling alley. Other times, it was bright and sparkly under all of that lighting and sometimes it did fluoresce, which is what I expected it to do most of the time. Is that normal for a SF stone to go dark in that lighting condition? I was expecting more of a blacklight effect since it was a bowling alley. I wish I took pics but I had family all around and too embarrassed to whip out the camera just for my ring. Lol

 

[OoohShiny]

So last night we did family bowling. Lots of fun! But I noticed my SF RB is dark inside the bowling alley. Other times, it was bright and sparkly under all of that lighting and sometimes it did fluoresce, which is what I expected it to do most of the time. Is that normal for a SF stone to go dark in that lighting condition? I was expecting more of a blacklight effect since it was a bowling alley. I wish I took pics but I had family all around and too embarrassed to whip out the camera just for my ring. Lol

Was it spotlighting? Strong single-point light sources (such as the sun or a single, bright spotlight) can create the effect, I think

 

[diamondsR4eVR]

Was it spotlighting? Strong single-point light sources (such as the sun or a single, bright spotlight) can create the effect, I think

Great question. That is possible. Even tho it was a dark room overall it did have all types of overhead lighting
Including LED. I need to read about spotlighting. Not familiar with that. I didn’t know since my stone is shallow 58.8 that may have been the cause for that to happen.

 

[Garry H (Cut Nut)]

Great question. That is possible. Even tho it was a dark room overall it did have all types of overhead lighting
Including LED. I need to read about spotlighting. Not familiar with that. I didn’t know since my stone is shallow 58.8 that may have been the cause for that to happen.

We would need a video and photos of the room and ceiling etc. A very effective way is to turn a spoon upside down and take a few photos using it to make an ultra wide angle system looking from the diamonds perspective at the lights.

 

[Garry H (Cut Nut)]

Looking back at this thread, Kristins example shows that a well cut round goes dark and the oval looks brighter.
The round has only a few very bright parts where as the oval has dozens of smaller not as bright flashes.

To say that the sunlight effect was startling (concerning!) to me at first is an understatement, since I was used to my oval (worn since 1999 engagement). I am learning more and understanding more these days, thanks to PS!

 

[diamondsR4eVR]

@Garry H (Cut Nut)
This is such a great thread and so fascinating! Prior to PS I would have thought the oval was a better cut than the round pictured above.

I now wish I took a picture of my stone when it turned very dark in the bowling alley.

 

[AV_]

@Garry H (Cut Nut) What does it take to rid the RBC of this darkness?

 

[Garry H (Cut Nut)]

@Garry H (Cut Nut) What does it take to rid the RBC of this darkness?

When you look at a really well cut diamond with only a very tiny light source that is incredibly strong (e.g. the sun which is actually really tiny except at sunrise and sunset) the chances of seeing a flash of light or any brightness is greatly reduced in proportion to the effectiveness of that diamond cut at returning light. Any flashes you see are sunlight directed straight into your eye which overexposes your eye and so the diamond looks darker.
When you take a photo with a camera you see with one eye only - and when you look at a diamond in direct sunlight with one eye the diamond will appear darker still.

Here I have a perfect round diamond with a small single light turned on in a otherwise dark environment:

And this is what that lighting looks like:

And here is a Jewellery Shop lighting set up in DiamCalc

 

[Halogirl1130]

This is really interesting. I found this thread because while I was in a big room with weird lighting and a black ceiling, my diamond looked BLACK. I couldn’t stop looking at it because I had never seen anything like it. It was so bizarre. I wish I knew what kind of lighting it was. It was really sparkly despite being so dark... it’s a 2.53 XXX I VS1.

 

[Garry H (Cut Nut)]

This is really interesting. I found this thread because while I was in a big room with weird lighting and a black ceiling, my diamond looked BLACK. I couldn’t stop looking at it because I had never seen anything like it. It was so bizarre. I wish I knew what kind of lighting it was. It was really sparkly despite being so dark... it’s a 2.53 XXX I VS1.

Great example - a nice bright diamond and a small bright spot light as the only source of light!!!

 

[KristinTech]

This is really interesting. I found this thread because while I was in a big room with weird lighting and a black ceiling, my diamond looked BLACK. I couldn’t stop looking at it because I had never seen anything like it. It was so bizarre. I wish I knew what kind of lighting it was. It was really sparkly despite being so dark... it’s a 2.53 XXX I VS1.

@Halogirl1130 I call that the “pop rocks” effect. Lots of flashes of color, it can be so intense that it seems like it should almost have audio and tactile input, lol. But yes, dark. It catches people’s attention from across the room in this type of lighting! My oval (pictured earlier in the thread) would do this only in the lively bow tie. The rest of the oval would remain white... so, kind of best of both worlds, I guess. I’m still learning about performance of both of my diamonds in different lighting.

 

[Texas Leaguer]

Very cool photos @Halogirl1130 .

The primary reason you are seeing black in this case is that the diamond is reflecting the black ceiling back to your eye.

Same reason that so many diamonds photographed outdoors look blue- reflecting the color of the sky.

What I find really appealing about your photos, is that this is what actual black diamonds would love to look like! But their body color precludes them, in most cases, from having any brilliance.

 

[Halogirl1130]

Very cool photos @Halogirl1130 .

The primary reason you are seeing black in this case is that the diamond is reflecting the black ceiling back to your eye.

Same reason that so many diamonds photographed outdoors look blue- reflecting the color of the sky.

What I find really appealing about your photos, is that this is what actual black diamonds would love to look like! But their body color precludes them, in most cases, from having any brilliance.

True! A black diamond that looked like that would be really cool!