| 1. |
In your Watermark Detector Tray add a small amount of Watermark Fluid, just enough to submerge the stamp.
Place the stamp face-down and its watermark should become visible as soon as the stamp is submerged. The stamp shown on
the right has a watermarked "S" on it.
|

|
Double Line "USPS"
|
| 2. |
Most stamps will only have part of a watermarked image on it. Do not expect to
find many watermarked stamps with full letters on them. Shown below, there are 2 complete
watermarked letters visible on this block of 4 stamps. The image on the left is unedited, while
the image on the right has been enhanced to better highlight the watermark.
|
  |
Single Line "USPS" U S P S
|
| 3. |
Some stamp issues from 1910 to 1916 have a single line watermark,
also spelling "USPS". These may be more difficult to spot as they are smaller than
a double line watermark and most of these stamps only have a small portion of the
watermarked letter on the back. For example the stamp on the right in the picture
below has half of a "U" on it.
|
| |
  |