German C40-C42 Counterfeit Identification?

Can an untrained eye spot the fakes of this issue? I have never seen, either the real stamps, or there forgeries in person. Are there 'tells' that I can look for?

One thing to look out for is line vs. comb perforated. The genuine ones are comb perforated. The GPS Forgery Manuals aren't real clear on this issue. They show two types of forgeries but with no explanation of what the differences are, and it's hard to spot any differences in the overprints with the pictures they provide. PostmasterGS will likely know.

Michel warns of overprint forgeries with the "Chicago" Zeppelin stamps, but not with the "Polar Flight" overprints. Maybe this is because the "Polar Flight" Zeppelins are overprints using a dark carmine brown ink. Both of these issues are overprints on basic German Zeppelins (C35-7) so they are all network pattern watermarked. If the perfs, gum, or paper (use uv light) are different, you know it is an obvious fake. If you don't have a reference copy of a genuine overprint, that could be a problem.

I will put up examples later today of the real and fakes .

If you're viewing them in person, the easiest way to distinguish them is the watermark (or lack thereof).

Additionally, the most common forgeries have line perfs, which can easily be distinguished from the genuine comb perfs.

If looking at a high-quality scan, there are also noticeable differences in the printing quality as well, but you'd really need to see examples to get the gist of it.

Great info everyone. Thank you.
I'm sorry, another question, can you tell me more about the line Vs comb perfs? This is actually the first I'm hearing those terms.

Floortrader, I would really appreciate those images.

This is a comb perf:



Look how perfectly the perfs line up at the stamps' corners.

Line perf has the horizontal and vertical perfs added independently, so they meet at haphazard points:



It is easiest to spot in blocks, but individual stamps are usually easy to identify, too, once you know what to look for. Catalogue values can differ quite a bit, so it is good to know how to tell.

Try these two out: I shouldn't turn this into a quiz.

Here is a block of St. Vincent that is clearly line perf, when you look at the center of the block.



and to compare, look at the middle junctions of this comb-perfed block from South Africa:



This is not one of those "None of the above" tricks...one is comb and one is line.

Sorry for the delay ,was out of town .

My first page of Zepplin forgeries .

Thank you all. This is fantastic!