Luxembourg Scott # O1 To O64

I recently purchased a very specialized collection. Included are a significant number of Lux overprints in scott ranges O1 to O64. Does anyone know how to spot the differences between authentic and counterfeit?

Please - Anyone in here able to give an answer on this old topic?

Well, apart from expertizing, it helps to compare more valuable stamps overprinted "Officiel" with overprints of the same type on cheaper and obviously postally used stamps. At least that's what I do.

There are relatively inexpensive Luxembourg official stamps with overprints of each type. If such a common stamp is postmarked, and if the postmark covers the overprint, one can safely assume that the overprint under postmark is genuine. Therefore, this overprint can be used as a template for comparison under strong magnification.

Page from Seranne Guide; make your own conclusions on this old subject as mentioned before.

What a helpful community - Thank you both!
The general rule to compare with a genuine stamp is naturally always a good indication.
And the spesifics from Serrane should help if in doubt - perfect. Now, where is my microscope....

hi: luxphilately.blogspot.com has some interesting articles. For instance December 2008 concerning officiel overprints..danger

perf12 - that's an interesting article. '
Merci