Offset Printing Detection

In Paul Schmid's book on the Washington/Franklin issues he suggests using very thin metal foil (350 microinches)to distinguish between offset printing and engraved printing.

Does anyone know where to obtain this foil? The only material I can think of is material for gilding, and it is very difficult to handle.

Thanks,
Mike

It's hard to tell differences by just looking at scans, but it's much easier to learn the difference by the look. Take or get stamps that only come engraved (#331, 332, 333 DL wmk) and see if you have or can get a #525 (typically a distinctive gray green), a #528 (type Va, only comes offset), #529 or 530 (types III or IV, also only come offset, many a distinctive bright violet). Just one value with one each engraved/offset is really enough.

Put values side by side and examine with a 10x magnifier. The engraved will show the raised, sharper lines clearly. Once you get it, you can pick out offsets easily without foil or magnifier.

Or do you just want the foil?

No, I don't really have any other need/use for the foil. I have gold leaf for gilding, but don't think that is very practical. The other method in the book was to use magnification and oblique lighting. Hadn't tried that yet, but it almost sounded like you needed to be in a dark room, usually not convenient.

Thanks, I will round up some samples and see if I can see a difference. Thanks,

Mike

A good 8-10x magnifier and low angle/oblique lighting make printing differences easy to identify.

As I am a Brit who does not collect USA (but who is most interested in printing techniques), I am unfamiliar with the stamps being questioned. With litho being a flat printing method and engraved being raised, does anyone know why this specific series is so difficult to distinguish processes? (And I am sure that it must be hard, or this thread would not exist.) GLENN

My thoughts:

Really not that hard with a little experience. 65170, with your interest, I'm confident that you could pick out the US offset stamps by eye, right now, and without a glass.

The US offset issues are anomalies among US stamps through the early 1970s, including the vast majority of back-of-the-book issues. There are only 15 major Scott catalog numbers of offset Washington-Franklins. They are then encountered very much less often in the oceans of cheap engraved stamps even though the group includes some very cheap stamps. There also has been no need in general to distinguish printing methods. Many US issues of the 1960s were often a combination of engraved and litho printing, but again, they only came one way, so there's no need to learn the different printing methods for them.

Several of the Washington-Franklin offsets also exist in unique types, easily misidentified despite the Scott diagrams. There are also several valuable stamps in the group that collectors may be trying to identify first before identifying the printing type -- information overload perhaps in trying to find these.

There seems to be fewer problems for worldwide collectors in the US, though offset fakes of engraved genuine stamps still fool many.

The Washington-Franklins would probably be better described as being produced by offset lithography.

EDIT: Also, online scans don't provide the education nowadays, shot flat and fully lit in a scanner and often being degraded JPEG to JPEG to JPEG copies by the time they reach a website.

Mike,

when I need to make sure, the foil I just take the thinnest they have in the supermarket, works well for me. instead of using finger I take a little fabric between finder and foil to make sure I do not damage

Separating out the offset printings by sight is relatively easy with experience and material, but.....
Beginning US collectors often only have a single stamp or two and thus nothing to compare against. Far more difficult with limited knowledge and limited supply.

This makes it easier:



Or obtaining a sampler set from a dealer. Here is the small Tasco Educational Booklet published in 1940 by Tatham Stamp Co, which provides samples of the types (except 1A of course).

Hy-Brasil, Many thanks for sharing your thoughts. GLENN