Question On A US A140 3¢ Washington

While the Perfin has obscured some of the design, I have identified this as A140, type II, flat press. What is baffling me is its size - 18.7mm wide (normal), but only 21.5mm high. Of course, flat plate is normally 22mm high and rotary press 22.5-22.75mm high. Of the many in this series I have viewed, this is the first I've seen with such a short height, so I'm looking for some guidance.

I would be looking at the offset printings, Scott 529 or 530.

The offset printings always seem to get overlooked. Once you identify a few, though, the color and appearance compared to the flat and rotary press issues will make them unmistakeable.

Thanks for that! While the Identifier of Definitive Issues section of the catalogue has a section contrasting Flat Bed and Rotary Press stamps, it has a dearth of information on offset printing. The only thing I found on line was "coarser and less detailed than flat or rotary. Also, the ink lies flat on the surface." I've found nothing on offset stamp dimensions, so anything y'all can provide would be greatly appreciated!

Ignore the dimensions until after thoroughly examining the other features like type, perforation rate, and watermark (if applicable). With a little experience, you will find that offset stamps "just look different" as mootermutt noted, with no size measurement ever needed.

Take a piece of tin foil and place it over the stamp. Rub the foil. If an impression of the design doesn't show, it's an offset printing... 529 or 530.