How to tell 10, 10A, 11 and 11A apart
There are several shades of each color. However #10 is a definitely orange-brown in appearance. #11 can be several shades of red, all the way from pinkish to claret. Above I have shown the two most common shades, dull red and brownish carmine and additionally the often seen shade of plum for #11A
Impression
The ink used to print #10’s was a high-quality formula of approximately 80 percent
Venetian red(ferric oxide/rust) and 20 percent
vermilion(red
mercuric sulfide). The ingredients not only gave the ink its distinctive orange brown color, but it also helped produce a superior impression, and its susceptibility to discoloration is very minimal (rust is the result of being exposed to the elements, and it is not susceptible to significant further discoloration). This first ink formula was discarded after about four months in favor of the brownish carmine shade. The reason for conversion to a new ink formula remains the subject of speculation. The iron oxide/vermilion mix certainly was more expensive, but rapid plate wear caused by the mercuric sulfide may have been an additional factor. Plate wear on this design began to show in the finest lines first. Some #10’s printed from plates 1e and 1i do show significant wear. Severe plate wear on this issue is most evident on examples from plate 1L printed in the late-1854 to early-1855 period.
In the image at left, the #10 shown at top left is an example of a high-quality early impression, while the #11 shown at top right was printed from a severely worn plate, with poor-quality ink. Note the lack of detail in Washington’s head, and the lack of sharpness in the rosettes and especially the tessellated (cross-hatch) work in the #11 impression. The #11 at right was advertised on the Internet as a #10.
Color
The image above shows an orange brown #10 overlaid on a sulfuretted (browned) #11.
The color and texture of the ink are key factors in #10 identification. Except for some rare anomalies, the color of #10’s fall into a narrow range of an orange/brown mix. Although this is stating the obvious, many sellers advertise stamps missing orange, brown, or both colors as #10’s simply because their color looks unusual, or deeper, than most 1851-57 3-cent imperforate stamps they’ve seen. The texture of the ink almost always appears thick and rich compared to #11’s similar in color. The #11 at right in the above comparison is of the orange red shade, commonly mistaken for orange brown, but the color looks pale and watered down compared to the #10.
Close examination of the sulfuretted #11 in the high-resolution image above reveals tiny specks of original reddish ink color in the low-relief areas in comparison to the blackened higher-relief areas of the inking. The ink used in #10 printings was not susceptible to significant discoloration from exposure to sulfides, although many #11 inks were.
Stamps are commonly advertised as #10’s because of their dark appearance. Sulfuretted stamps are stamps printed with higher concentrations of ferric oxide in the ink formula that have been discolored by exposure to sulfur dioxides (commonly found in air pollutants).
Sulfur dioxide(sulfide) exposure converts ferric oxide (found in
Venetian red(
ferric oxide/rust)-based pigments) to ferric sulfate (dark brown).
Cancels
A June cancel confirming the stamp is NOT a #10, but the less valuable #11
Cancellations can be used in limited cases to help confirm or rule out a stamp as a #10. In the 1850s letters generally were carried by the sender to the post office for mailing, and only the stamps needed for that day’s mailing were purchased,. The stamps were immediately affixed to the letters brought in for mailing. Stamps used more than a few months after distribution to the post office were the exception. The earliest known use of Scott #10 was July 1, 1851. Approximately 98 percent of #10’s were used by the end of May 1852, so any examples dated with a June date stamp are almost certainly #11. There are only a few confirmed contemporary usages of #10s after 1852 (2/10/53, 6/26/54, and one in 1858).
#10 with a BLUE Philadelphia date stamp
#11 with a BLACK Philadelphia date stamp
Philadelphia cancels also can be used as dating aids, since Philadelphia abruptly converted from blue to black ink for their cancellation hand stamps on about January 1, 1854. The #11 above, although strong in orange pigment and lacking good plating marks, could not be a #10 because of the black Philadelphia April cancel (and worn-plate impression).
