Visual Diamond Brightness

[Karl_K]

Visual diamond brightness
How bright a diamond looks is relative to the contrast it provides against the background it is against.
True or false?
Which is the brighter "diamond"?

 

[Karl_K]

How about in this image?

 

[Regular Guy]

Logically, Karl, it's option #1.

By observation, I don't find value in the first example to make a judgement, and based on the size, the second example is only marginally better, but I could confirm slightly option 1 there.

Ira Z.

 

[Karl_K]

How about this one?

 

[Rockdiamond]

This is a very interesting, and timely topic.

Clearly, a darker background increases perceived brightness.
Take a lit candle- if we look at it in sunlight, it's not bright at all- of course in a dark room it's very bright.

Besides contrast of background, lighting plays a key role as well.
I have long questioned "brightness" measurements as they seem to be overly simplistic.

 

[Paul-Antwerp]

This is a very interesting, and timely topic.

Clearly, a darker background increases perceived brightness.
Take a lit candle- if we look at it in sunlight, it's not bright at all- of course in a dark room it's very bright.

Besides contrast of background, lighting plays a key role as well.
I have long questioned "brightness" measurements as they seem to be overly simplistic.

David,

Are you looking at that candle with the sun as background?

 

[Rockdiamond]

Good question Paul.
Actually, I just tried ( although it's not too sunny today)

SO- let me rephrase.
A candle is perceived as far brighter in a dark room as compared to looking at one in sunlight

 

[Paul-Antwerp]

Good question Paul.
Actually, I just tried ( although it's not too sunny today)

SO- let me rephrase.
A candle is perceived as far brighter in a dark room as compared to looking at one in sunlight

Then, what is the relationship of your remark to the original post, which talks about background?

 

[Rockdiamond]

As I wrote Paul- IMO darker background increases perceived brightness.

My intention was to respond to Karl's question

 

[Garry H (Cut Nut)]

I posted this recently - I think it shows what is being discussed.
Exact same lighting.

Also look at your hand with a window as a backdrop, then move it away from the window just a little - your eye adaption to the background is remarkable.

 

[Rockdiamond]

Illuminating photos Garry.
Which scenario is optimal for accurately showcasing diamonds ( in your opinion)

 

[yssie]

I have dark skin.

My diamond looks much brighter and whiter on my hand than it does wedged into the tip of my DH's very pale pinky.


What does this mean for me? When I'm shopping for a diamond, I know that I can drop colour (and price) and still appear to have a "white" diamond. My best friend (also very pale) will just have to cough up for a diamond that actually has less tint if she wants her stone to 'match' my stone's apparent whiteness when worn. So hand models should be very pale, to ensure the customer spends as much as possible on colour

Karl and David are addressing two very different sides of the question - what actually happens, which can be measured (ie. using the term 'brightness' as an objective observation of some measurable quantity, through reflector technology, etc.), and what the human eyes see - and as Garry's pictures illustrate so well, the two often don't correlate.

 

[Karl_K]

The reason I posted this is 3 fold.
1: When viewing vendor pictures the color of background matters.
2: A diamonds lighting environment goes 360 degrees around the diamond when considering diamond performance.
3: all forms of diamond brilliance can be defined as contrast (much much more on this later, as there are many types of contrast to take in account both internal and external to the diamond)

Once we understand contrast in its various forms we can look at how virtual facets create contrast.

 

[Karl_K]

I have dark skin.

My diamond looks much brighter and whiter on my hand than it does wedged into the tip of my DH's very pale pinky.


What does this mean for me? When I'm shopping for a diamond, I know that I can drop colour (and price) and still appear to have a "white" diamond. My best friend (also very pale) will just have to cough up for a diamond that actually has less tint if she wants her stone to 'match' my stone's apparent whiteness when worn. So hand models should be very pale, to ensure the customer spends as much as possible on colour

Karl and David are addressing two very different sides of the question - what actually happens, which can be measured (ie. using the term 'brightness' as an objective observation of some measurable quantity, through reflector technology, etc.), and what the human eyes see - and as Garry's pictures illustrate so well, the two often don't correlate.

*grin* will keep that in mind if I ever open a store.

Reflectors show "potential" brightness in a simplified environment not actual brightness.
Brightness in reflectors is a totally different topic.

In Garry's pictures it is possible to pick out the less well cut one in every image.

 

[ChunkyCushionLover]

It should be a requirement in every Diamond Research thread to define the terms and properties being observed.

Definition of Brilliance using AGSL's definition(related to measured brightness in reflectors):

For understanding the illumination appearance of a gem it is useful to think of a gem’s facets and their optical projections,
the virtual facets, as a collection of tiny prisms that direct light to an observer’s eyes. Thus brilliance(brightness) is defined as the percentage by area of such tiny prisms that can direct light to the observer’s eyes.

GIA's definition of brightness(they use this term not brilliance to avoid it being mistakenly associated with contrast):
(G&G Fall 2004)

The appearance or extent of internal and external reflections of "White" light seen in a polished diamond when viewed face-up.

 

[Garry H (Cut Nut)]

Illuminating photos Garry.
Which scenario is optimal for accurately showcasing diamonds ( in your opinion)

As Yussie said - the best would be with hand as a backdrop.
Sitting in between two fingers is great if you can hold still enough

 

[Paul-Antwerp]

On a totally different note, is the choice for the word 'brightness' in the title of this thread the best choice?

Some people use 'brightness' as a synonym for 'brilliance', while the subject here is clearly more about 'transparency'.

Live long,

 

[Garry H (Cut Nut)]

On a totally different note, is the choice for the word 'brightness' in the title of this thread the best choice?

Some people use 'brightness' as a synonym for 'brilliance', while the subject here is clearly more about 'transparency'.

Live long,

Sorry Paul - are you in the right thread?
There is another in this research section on that topic.

 

[Paul-Antwerp]

I am sorry. I totally confused two threads, and my comment is completely off. My apologies.

 

[Karl_K]

no problem Paul even off topic you brought up a good point.

What I was trying to do is separate potential brightness from real world brightness then separate brightness from contrast then bring them back together as light performance.
As part of LP they need to be considered separately in order to understand what the reflectors in particular are telling us.

Any help with wording would be appreciated.

 

[Rockdiamond]

Glad to see you back Karl
Great thread- there's little question in my mind that the terminology is a challenge.
Kind of like trying to describe what "blue" is.
We can point to the sky- but even then, people's perceptions differ.