The stamp above (US 212) was printed on the
"soft porous" paper of the American Bank Note Issues. Note that the poor centering
providing two wide margins makes identifying the paper type much easier,
something to keep in mind while learning to differentiate the paper types of the Bank Note issues.
The traditional technique is flicking the stamp near one's ear. A crisp sound will in most
cases identify the stamp as being either a National or Continental printing, but a duller sound does not necessarily mean the stamp was
printed by the American Bank Note Company.
For most of us the simplest method for determining whether the stamp was printed by the American
Bank Note Company is to hold the stamp to a strong light source at
various angles and determine whether the paper has a mottled, opaque appearance. If it does, it is American, if not, it is either a National
or Continental printing.
If you are unfamiliar with this "mottled" look, find some of the stamps shown in the Bank Note Identifier that have the term "Redesign"
in their description. All of these stamps were printed only on the "soft porous" paper.
Perhaps easier, all of the of 1893 were printed by the American Bank Note Company on "soft porous"
paper and they may prove more useful in getting a feel for the "soft porous"
paper. As mentioned, if the stamp has a wide margin or selvage the mottled
look is very evident and many of the Columbians do.
Compare these with a stamp from the 1869
Series. Multiple copies of US 114, for example, can be had at
nominal cost. (Note that the 1¢ Special Reprint of 1880, US 133, was printed by the American
Bank Note Company on the soft porous paper.)
There is perhaps an even better way to determine whether
the stamp is the "hard white" or "soft porous" type, but
you need to have a good ultraviolet source to see it. The "hard
paper" stamps will "shine" a little brighter than their
"soft porous" counterparts. although this difference can apparently
be seen with the cheaper UV lamps, at least to this observer, the difference
is very, very slight. With the more expensive UV lamps this difference is more
There are many other differences in paper type, for example "ribbed" paper, the very white paper of the Special
Printings and even double paper printings.
For more information on the subject of stamp paper types we recommend the following reading:
Brookman's "The United States Postage Stamps of the 19th Century"
The Stamp Specialist Number Four, James H. Obrig: "Paper. A
Non-technical History and Description of the More Common Types as used in
Philately" - which includes eight paper samples
Lowell Cooper's "Some Notes Concerning Paper
and Paper Mesh on the Bank Notes"
R. H. White's Encyclopedia of the Colors of United States
Postage Stamps Volume 6: "Paper and Gums of 1847-1909"