(I think) The best way to check rubies

[Tudor]

So, I haven’t used film in over a decade. But when I did, I proofed my negatives on a light table. I have a battery powered portable one I have re-purposed for inspecting rubies and their bores. 

Any crack or spec of dirt is easily seen when back lit. Lighting from the top only, can hide cracks. Lighting through the stones makes any flaw easily apparent. 

No idea if these are still available but probably. It runs on batteries and has an A/C adapter. 
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[canthus]

I use my smart phone or tablet.  Just find a white area and place the plate on it and use an eyeglass for closeup.  You can see the pixels but this is not too much of a problem.  I have also tried a daylight LED bulb with white paper over it but it was a bit too bright and didn't want my eyes damaged when using an eyeglass.

[Tudor]

That’s a good idea too!

[Klassiker]

If you use your phone, you will need to demagnetise afterwards.

[Malocchio]

Has anyone come up with some cheap and small (thin) backlight for jewel inspection? I still have this microscope that I only use for inspection purposes but if I found some backlight I could use with my newer sm-4tp I could sell this scope. I'd rather have some dedicated piece instead of phone display or such.

[tomh207]

19 minutes ago, Malocchio said:

Has anyone come up with some cheap and small (thin) backlight for jewel inspection? I still have this microscope that I only use for inspection purposes but if I found some backlight I could use with my newer sm-4tp I could sell this scope. I'd rather have some dedicated piece instead of phone display or such.

I am thinking about getting one of these for this

https://www.amazon.co.uk/gp/product/B0BKSLZ27K/ref=ox_sc_act_title_3?smid=A3UR61Y1YXNUGU&psc=1

Tom

[JohnFrum]

I use a little LED keychain light I bought in a discount store. Piece of paper and I have a backlit base for examining parts under the microscope  

[rehajm]

Does it have to be direct backlight for some reason? Shine a penlight on your work mat underneath the movement and  the jewels are easy to inspect. Looks like an x-ray, yah?

[Malocchio]

Thanks for the suggestions. I think penlight would be ok for inspecting but I'd also like something I can put the movement holder on top of when checking pallet lubrication. I might try putting something like a mirror under the movement next time.

[HectorLooi]

A microscope with a ringlight would be best. But if you are just looking for a small light box, you could take a photo of a white sheet of paper and open up that photo everytime you need a backlight. 

[Malocchio]

A little update. I found a nice usb powered light panel from a flea market for 5€. Really flat and surprisingly bright, nice for jewel inspection.

 

Edited March 22, 2024 by Malocchio

[mikepilk]

On 5/20/2023 at 7:01 AM, Malocchio said:

Thanks for the suggestions. I think penlight would be ok for inspecting but I'd also like something I can put the movement holder on top of when checking pallet lubrication. I might try putting something like a mirror under the movement next time.

I use a stereo microscope with light ring. When lubricating the pallet jewels, I sit the movement holder on a mirror and use an LED headlight shining down at an angle on the mirror, so that it reflects up through the movement.

 

[Waggy]

Maybe something like this??