Fraudulent Bottle Colors?

[Diggrrr!]

I hope someone can shed light on this for me.

Lately I've been seeing some oddly colored bottles on eBay, and I am uncertain whether the colors are natural. I know that the ultra-deep purples are almost certainly bottles with manganese glass that have been heavily "nuked" with UV. But I have also seen an extreme teal Bixby ink and an extreme teal Carters ink. The colors do not look natural, or perhaps it would be more accurate to say that I, personally, am surprised by the vividness of the colors. Is the information age merely allowing me to view some of the very rare bottles that I would normally never see or are unscrupulous sellers somehow altering their wares?

Thanks!
diggrrr!

 

[GuntherHess]

Those bottles are sometimes found on deep aqua or teal. I would say it is very possible they are perfectly natuaral examples. Its hard to tell without seeing the specific bottle.
I have noticed quite a few people selling bottles that are painted with a transparent color coating to make them odd colors. So far the ones I have seen for sale have been marked as artifically colored.

 

[Diggrrr!]

ORIGINAL: GuntherHess

Those bottles are sometimes found on deep aqua or teal. I would say it is very possible they are perfectly natural examples. Its hard to tell without seeing the specific bottle.
I have noticed quite a few people selling bottles that are painted with a transparent color coating to make them odd colors. So far the ones I have seen for sale have been marked as artifically colored.

If a bottle *was* coated to change the color, any idea what solvent one would try to test the deception? I would guess that a transparent color coating would have to be made from a polyurethane or clear acrylic. Other possibilities?

Thanks for the info!
diggrrr!

 

[IRISH]

It depends what the substance used to colour the bottles is made up of, I've heard that there has been coloured codd's made up that are almost impossible to test with solvents although everything is soluble in (or reacts with) something.

If you try Actone, Toluene and something like Hoppes No.9 gun solvent they will between them remove most transparent color coatings I can think of.
If you expose a suspect item to a long and short wave ultra-violet light source the different fluorescence should give the game away [] .

 

[GuntherHess]

The color coatings I have see so far will come off if you scratch them with a knife blade.