Why does RB cut look better in shade than under the sun?

[zhuzhu]

I don''t really understand the technical reasons behind it. No matter how good a RB cut diamond is, it always look more "dirty" directly under the sun compared to its look in the shade. In the shade they glow beautifully with fire and brilliance, but not so much under the sun.

Why is that?

 

[stone-cold11]

they still perform well, too well in fact is what you are seeing. Too much light is being reflected back into your eyes resulting the pupils contracting, making the stone look less bright.

 

[zhuzhu]

Interesting!
But if that is the case, why does camera also have a hard time picking up the expected performance?

 

[stone-cold11]

same thing, if you look at GOG''s video, between diffuse lighting and spot lighting.

 

[kenny]

Latitude is the range of light captured, from dark to light.
The eye and the camera both have an iris (hole) to close down when things are bright and open up when things are dark.

Besides the iris the eye has a retina and the camera has a CCD or film; these are the transducers that change light into electricity.
All three have a limited range or latitude.
BTW the human retina has a much wider latitude than any CCD or film.
It is the job of the iris to attempt to adjust the light so it fits as well as possible into the latitude of the retina or CCD/film.

When the range of brightness exceeds the latitude of the retina or the CCD or film they are no longer able to capture all of the detail in the highlights, the shadows, or both.

To digress, there is a new photography process called HDR, or High Dynamic Range; it's stunning!
Your camera takes 3 pics one with the iris small for the highlights, one with the iris open for the shadows and one in between.
Then software like photoshop combines the 3 images to produce a pic that is astonishingly life like with wonderful detail in the shadows AND the highlights.
These HDR images can seem live because we are not yet accustomed to seeing captured images with the wide dynamic range that the human eye can capture.

As mentioned the highlights in a diamond in the sun makes your eye's iris close.
A closed iris lowers the intensity of ALL of the light levels present in the diamond.
This makes the non-highlight portions seem dark.

A camera can be forced to place either highlights or the shadows into the latitude that the CCD/film can record, but usually cameras are on automatic exposure mode which attempts to achieve some average balance.
Some subjects exceed the latitude of the CCD/film and produce unsatisfactory results.

 

[kenny]

Sorry I got carried away and didn't answer your question.

The reason diamonds look better in the shade than sun is the range of light from them in the shade fully fits within the latitude of your iris/retina system.
You can see all of the detail in the brightest and darkest parts of the diamond.

This is not true in the sun.

You could visualize this with numbers and units I'll just make up.
Let's say the iris/retina can make out from level 30 to 80.
30 to 80 is the latitude.
Every light level darker than 30 just looks black like 30.
Every light level brighter than 80 just looks white like 80.

If the light from a diamond in the shade falls, say, from 40 to 70 it is easily within your eye's latitude; but in the sun it may be from 55 to 265, far exceeding your eye's latitude.
The absolute numbers don't matter; what matters is understanding that the light range present in some subjects exceed the range of the eye, and moreso the range of your camera.

 

[Todd Gray]

Explained very well thus far, but I wanted to add that diamonds need a little contrast as provided by things like trees, tall buildings, etc. in order to perform really well. In fact, diamonds look wonderful under a leafy tree on a day with a slight breeze because the sun is broken up as it passes through the leaves (creating contrast) and this causes the light to move about as it bounces off of the diamond (creating more contrast) and then the diamond sparkles!

 

[kenny]

I found a booboo in my first post.
Film does not change light into electricity, but is does also suffer from a limited latitude just like the retina and the CCD.

 

[zhuzhu]

I love how clearly and beautifully you have all answered my question. Thanks!

 

[jlx]

i actually think RB stones look better in the sun than the shade!

 

[Rockout]

Date: 3/23/2010 6:26:20 PM
Author: Stone-cold11
same thing, if you look at GOG''s video, between diffuse lighting and spot lighting.

I am not a diamond expert but have studied photography and more specifically lighting and I agree with this assessment. The sun is considered a hard (small) light source as it comes at the subject in one direction. Same with straight on flash photo''s - they tend to come at the subject in one direction, producing hot spots and hard shadows.
Soft lighting such as overcast days, shade or indirect light tend to produce soft light as the light rays are diffused and they hit the subject from many directions. Soft light produces far fewer shadows and it tends to wrap around the subject.
This is perhaps why you are seeing more light return in the shade than when the diamond is in the direct sun light.

 

[Stephan]

Date: 3/23/2010 9:57:45 PM
Author: jlx
i actually think RB stones look better in the sun than the shade!

It also depends on the cut.
A few topics exists about how dark H&A can look under the sun.