Idealscope question

[JDgirl]

I did a search, but I can''t seem to find the answer to my particular question. If an idealscope measures the brilliance, or light return from a diamond, then why do you backlight a diamond when looking through the idealscope at it? I don''t understand how shining light through the back of the diamond helps measure the light return when all light returned must enter through the face? Am I making sense? So why doesn''t the idealscope need the light to enter through the face of the stone?

 

[belle]

reflector viewers such as the idealscope do not 'measure' anything. it is a simple tool that shows areas of light leakage. by lighting the stone from the back, you are able to note areas where light will escape though the bottom of the stone as it passes through the top in normal viewing conditions. a diamond that leaks light through the stone will not perform well since the main objective of a diamond is to be reflective (sparkly)

 

[JohnQuixote]

The ideal-scope creates a structured light environment to show overall light return.

Light coming from directly above is blocked by your head, or the camera, so light drawn from/returning to extremely high angles is dark (often black in photos).

Light entering at optimum angles comes through the colored tube first - then comes back to your eye - so it is red if it's returning properly.

The white light from behind should not be coming through the diamond if all of the light from directly above (black) and from optimum angles above the crown (red) are properly returned. If you do see white it's backlighting coming through in areas where the light from above is not reflecting back (we call it 'leaking').

 

[oldminer]

The Ideal-Scope is a great comparator or screening tool, buyt as you have been told, it does not "measure". Nothing is better for quick screening groups of diamonds for which ones perform the best of the bunch. It works great for taking a look at three or four stones in order to assist your eyes in seeing which diamond might be best or which ones might be a liittle less bright. The most major thing is that it is intuitive and not technical. Anyone can learn to use it in less than a minute.

 

[JDgirl]

Thanks for the explainations! I get it now!