The first step in the determination of whether a stamp has a
particular watermark is to remove any hinges or other foreign
particles (please consult an experienced collector about removing
hinges and foreign matter, many a stamp has been damaged by the
careless removal of such), gently place the stamp in your tongs
and hold it against a strong light source face forward at various
angles, being careful not to damage the stamp from the heat of the
light source. Often the watermark will come into view, particularly if
the watermark is in an area that is not inked. Stamps with a large margin or selvage are prime candidates for this. You have
probably seen a photo or scan of a block of stamps where the
watermark is clearly visible in the selvage. You should also be aware of abnormalities in the stamp
itself: thins, creases, tears, lines in the gum, a heavy cancel,
heavy ink or lack thereof, and make a note of where on the stamp
these abnormalities occur in order that you not confuse them with
a watermark when using a technique outlined below.
The importance of viewing the stamp from many angles cannot be
over-emphasized. This applies to any method described in this
If the watermark does not come into view when held to a strong
light, the stamp should be dipped in fluid, preferably face down.
Two of the more prominent types of watermark detection fluids are
discussed in another section.
To test your ability to find and distinguish watermarks, the
perforated 12 Washington Franklins (WFs) provide the greatest
opportunity for U.S. collectors. All perforated 12 WFs have a watermark. Some
have double-line watermarks and some have single-line watermarks.
You should hone your technique until you can identify a watermark
on nearly every perf 12 WF you can get your hands on.
We say "nearly", because the single-line USPS
watermark found on U.S. stamps can often be extremely difficult to
detect, particularly on orange stamps, but also on yellow and
light (olive) green stamps and also on heavily cancelled stamps.
Further exacerbating the problem, the single-line watermark is
smaller than the double-line
watermark. It is
possible that only tiny parts of the letter(s) on a particular
stamp are present, often giving the impression that a watermark
does not exist. On the other hand, imperfections in the stamp may
create the impression that a watermark exists
when one doesn’t. To make matters worse, on some of the later
stamps the impression of
the single-line watermark on the paper stock became increasingly weaker, to
the point of appearing slightly fuzzy, making detection
even more difficult.
Become familiar with the design, size and layout of the
single-line watermark. Familiarity with this drawing will help in gaining
perspective. However, there is nothing like the experience of
finding the actual watermark. This is why we
can not over-emphasize spending the time with your perf 12 WFs to
familiarize yourself with the way the single-line watermarks seem
to "hide" in the corners of the stamp. Any perf 12 WF
that does not seem to have a watermark provides you with a great
learning experience, since it MUST have a watermark.
If necessary, the difficult perf 12 WF should be dipped and
re-dipped, examined in the tray or held to a strong light source at various angles until the
"hidden" watermark manifests itself. Pay particular
attention to two critical intervals, one when the fluid is just
beginning to be absorbed and the other when the fluid is just
about to dry. Watermarks and other imperfections in the stamp
paper often miraculously come into view at these critical moments,
albeit briefly. Applying the fluid with an eyedropper will aid in
prolonging the moment of initial absorption. Keep in mind that on most of the more difficult stamps,
there are tiny parts of several letters on the various
edges of the stamp and that the USPS lettering can appear reversed
and/or upside down as well as "normal" (see the
eight possible orientations).
If after several unsuccessful attempts at finding parts of any of
the letters "U" "S" or "P" on the
perf 12 WF, you may want to try using a colored filter. If you’re
really serious about this, you may want to try a photographic or
scientific supply house to get filters specifically designed to
remove light of a specific color. Alternately, we have found that
colored cellophane wrapping paper, for example the kind that fruit
baskets come in, often does the job. Either way, you will want to
use a filter of the complimentary color of the stamp in question.
For example, you would want to use a blue filter for the difficult orange
stamp, a purple filter for the yellow stamp, and a red to reddish
violet filter for the olive green stamp. The filter
should be translucent enough to let plenty of light through and
yet block the color of light reflected from the ink of the stamp.
Alternately, you may want to experiment with the color of the
tray the stamp is placed in, again using the complimentary color
of the stamp for the tray. We have found that the less glossy the
tray, the better the results. Thus, opaque glass and ceramic trays
often do a better job than the shiny plastic ones.
You may also want to experiment with the light source.
Fluorescent light is particularly poor at displaying objects in
the red range. This is why indoor photographs often have a
greenish tint. Natural sunlight has the greatest range but the sun
isn't always convenient. To get most of the visible wavelengths of the
solar spectrum without using natural sunlight, it is
possible to purchase an "all wavelength" light bulb in
most hardware stores at nominal cost. This "all
wavelength" bulb may also prove useful in determining the
true color of your stamp.
Other points that may prove
1. Simply knowing that a particular
stamp has a watermark and knowing what that watermark must
look like, makes finding the
watermark that much easier. Study the printable templates and the
actual illustrated blocks on the watermark pages until you are
quite familiar with the shape and size of each letter. We would
also recommend taking a close look at the example on the single-line
watermark page and reading the example
below it carefully.
2. Many experienced collectors can sort
non-watermarked "First Bureaus", the
"Triangles" - US's 246-263, from their double-line
watermarked counterparts, US's 264-278 merely by examining the
raggedness of the perforations. If the perforations are not ragged
there is a good chance the stamp has a watermark. Be suspicious of
any Scott 260, the 50c orange, lack of ragged perfs are a great
indicator that the stamp is the less expensive, watermarked US
3. Some watermarked stamps were issued in certain shades of color only. It
is sometimes possible to separate these stamps by color or shade
alone. The Scott catalog is an excellent reference for these
shades and we will add to this as time goes by.
The use of any or all of the above techniques mentioned above may
just bring that elusive watermark into view.