White Field or Dark Field ASET

[tcmayer]

seems like James Allen no longer do ASETs in white lighting.

Is there any particular reason for this?

From the way i see it, the white field ASETs enables us to see leakage and the different (Red,Green,Blue) colors easily.

The dark field images shows black as leakage and very often, areas in which the white field ASETs show blatant light leakage shows up as green on the dark field.

- the dark field aset seems to make diamonds look better with more greens instead of showing blatant light leakge.
- dark field aset show blended colors between red/green/blue. It's hard to discern image properly.

All of these points to making the stones look better than they actually are instead of helping consumers better determine light performance objectively.

if there are any other explanations, could any knowledgeable guys share the pros and cons between dark and bright field ASETs?

 

[Karl_K]

I think that white background is easier to read but that black background may be more accurate to the real world.
I feel that white backgrounds slightly exaggerate leakage compared to the real world.
Then again black backgrounds may slightly understate it, but still feel it may be closer to real world.

With a white background areas with 50% leakage will show white and with a dark background they will often appear a mixed color, that is more accurate to the real world.
The intensity of the back-light makes a large difference with the white background.
If the light is bright enough even areas of ~75% return can appear white.

Many areas of leakage are not leakage as in a window they are the diamond drawing light from the bottom rather than the top.
Since they are prisms rather than mirrors they can draw light from more than one direction so a mixed appearance can be more accurate than over powering white light from the bottom.

Showing absolute leakage for showing the highest cut quality, I do prefer white backgrounds because at that point id be looking for the technical best of the best not if it is good in the real world.

 

[Rhino]

I hear what you're saying Karl but having done both I prefer the bright background personally. Blacks/blues can be very confusing. I'm even considering dropping red reflectors altogether as our ASET against white tell the whole story from leakage on the pavilion to where the input is coming from via ASET.

 

[tcmayer]

thanks for the insights.

another question. This is not aimed at James Allen personally as I see many other online vendors with both black field aset and white field asets on the Internet.

which of these is easier to manipulate or be error prone?

For example, some vendors might knowingly or unknowingly take aset images that don't necessary reflect the performance of the stone.
Possibilities here include:

- I am thinking along the line of purposely jacking up or turning down contrast so that the diamond looks better than it is.
- genuine errors when a vendor doesn't operate the machine well, a great looking stone might be missed because of poor use of ASET.