Gum: Original or Not?
By Peter A. Robertson (Excerpted from "Opinions
Without question, the most valuable commodity in our
hobby today is gum. If you do not believe this, just compare auction
realizations where similar copies of a stamp may vary in price as
much as five or six times depending on the state of the gum on each.
Centering and freshness also playa part in determining value, but
gum condition seems to be the most important factor in actual pricing.
Gum is also the most misunderstood aspect of our hobby.
The term "original gum" is used universally
by dealers and collectors alike. It refers to the adhesive on the
back of a postage stamp, intended to attach the stamp to a letter
or parcel when moistened. On an unused stamp, when this gum remains
the stamp is described as having original gum. The optimum condition
for this gum is to be in exactly the same state as it was in when
it left the post office. This is referred to as "mint, never
hinged". The small, gummed paper hinges that were popular in
the earlier days of our hobby - before protective mounts - were clean,
usually easily removed, and left only a light outline on the gum
where they had been attached. Today people are quite willing to pay
a premium for "never hinged", although few know why.
Actually, paying extra for never hinged
stamps was a practice started by individuals who did not know very
much about stamps. They were trying to protect themselves from buying
damaged or repaired stamps so they insisted upon "never hinged".
The fact that most early issues no longer exist in this condition
has never impeded these individuals in their search. And, of course,
where someone is willing to pay extra for something, that something
is always made available by some of the shadier characters in our
Now, it is true that it is difficult to sell stamps
where remnants of previous hinges are present. Because of this, removal
of old hinge traces has become an art rivaling gem-cutting. Surgical
and dental tools are used by highly skilled artists to remove old
hinge remnants. The logic of this is that nothing should be hidden
by hinges still attached to the stamp.
To make the removal job easier, the stamp is put into
a very damp environment where the gum on the stamp is actually liquefied,
that is, made completely liquid or melted, just as it was when first
applied. Hinge remnants can then be lifted right off the stamp without
damaging it. By taking a fine brush and redistributing the remaining
gum, the traces of previous hinging can be hidden from all but the
most expert eye. The gum here is most certainly original - nothing
has been added - but the state of the gum is most definitely changed
from its original condition.
This change occurred as the gum re-dried. While what
remains is original, the gum is thinner due to some having been removed
during the brushing process. Also, the environment where it dried
after hinge removal is entirely different from that following its
original application. Certain changes in the appearance of the gum
Before we examine these changes, it is important that
reader understand what original gum looks like. The application of gum
to a sheet of stamps was done rapidly and in a single motion. On the earlier
issues of United States stamps, this gum tended to be rather thick, and
the gum was intended to be applied entirely across the sheet. As is the
case when one applies paint with a brush in a long stroke, areas develop
where there is no paint. Usually elongated thin lines called "skips"
result, elongated in the direction of application. Gum skips are quite
natural and exist on most of the older U.S. stamps. These stamps are often
filled in or erased when original gum is redistributed. It becomes important
to know typical gum for any particular issue of stamps.
Figure 1 illustrates the typical gum on the
1893 Columbian issue. Note the long streaky gum skips running horizontally.
The upper portion of the picture shows the outline where a hinge
was removed. A close examination shows that all traces of gum skips
have been erased where the hinge was, while the normal skips show
Figure 2 shows the typical gum found on the
Trans-Mississippi or early Twentieth Century issues. While the gum
here is thinner and smoother, a very close examination shows fine
streaks in the gum elongated vertically. The reader can easily see
where a hinge was removed. The original gum has been seriously affected,
and it no longer resembles the gum around it.
Additionally, one often finds the light outline of
perforations impressed in the gum on these later issues, probably
as a result of sheets being placed one upon another when they were
perforated and while the original gum was still damp. These faint
perforation traces are very helpful in determining if the gum is
original. The process of gum redistribution will either erase these
perf traces or make them far less visible to the naked eye. The fine
row of horizontal perforation traces in this example has been completely
eliminated where the hinge was removed.
These two examples should help the reader to understand
better original gum and its characteristics. We can now discuss those
changes resulting from the melting of gum to remove hinge remnants.
When gum is dried too quickly after the redistribution
of the original gum, it will crackle all over (see Figure
If dried too slowly, the moist gum will run into the
broken paper fibers around the perforations and their teeth as shown
in Figure 4. The stained areas around most of the perforations on
this stamp were caused by dampened original gum running into the
body of the paper through these broken fibers.
Reproducing the same conditions under which original
gum was applied and dried onto stamps is virtually impossible. Therefore,
almost all stamps with redistributed original gum have gum which
does not match the normal gum for that issue.
A simple comparison copy is all that is needed to detect
gum alteration. It seems obvious that a stamp with good original
gum can be used as a control copy against which all possible acquisitions
can be compared. This writer would recommend the purchase of a fresh
copy of a low value of a set having both a straight edge and a hinge
remnant attached. This type of stamp has little value as a collectible,
but will serve as a very valuable comparison tool so long as the
original gum is fresh. The important thing to remember is that the
same gum was applied to the 1 cent Columbian as to the $4 or $5 of
that issue. The inexpensive stamp, therefore, can prove to be very
valuable in the long run.
Up to now we have avoided the word "regummed".
Most of the stamps that the collector will encounter will not be
regummed. But some will be, and the collector should know enough
to protect himself. There is often little difference between a stamp
with redistributed original gum and one that has been regummed. This
is not unusual as the basic processes differ very little. A stamp
having hinge remnants removed may have additional gum added to the
liquefied original gum. If the job is done well, it may be extremely
difficult to tell, even for an expert. Fortunately, most are not
Stamps almost always are regummed to hide defects.
A tear in the paper can be closed and the repair substantially hidden
under a good coat of gum. There may be evidence showing faintly on
the face of the stamp, but it will be almost impossible to see this
type of repair through the gum. Another repair that is often hidden
under regumming is the addition of a new margin.
Probably the most commonly hidden fault is a thin spot.
Thin spots are shallow depressions in the paper caused by the improper
removal of something attached to the gum. This might be a hinge,
an album page, or anything else to which the stamp got stuck. Some
thins are tiny and are easily covered over with new gum. This type
of repair may be very difficult to find, even in watermark fluid.
Other thin spots could be large or deep. This type cannot be covered
with new gum as it will still appear when the stamp is immersed in
fluid. The repairer will often try to fill in this type of thin spot
with a foreign substance, usually in a paste form. New gum is then
applied over the repair.
The stamp on the right in Figure 5 has been repaired
extensively. Large thinning from the center of the stamp to the top
has been filled in and covered over with new gum. The stamp on the
left shows the normal gum for that issue. A close examination shows
how very different the two stamps appear. Regumming is nothing new.
It has been with the hobby since the 1860's or early 1870's. The
only change has been in the methods used. Each method leaves its
own evidence, almost a signature. So let's examine a few.
The latest development in painting has been applied
to regumming: the spray gun. Spraying requires air, and air dries,
leaving bubbles as shown on the right stamp in Figure 6. Sprayed
gum also appears much more shiny than the normal gum of the issue,
compared at left. These bubbles can be brushed away, however, so
be careful. A close examination should reveal enough differences
to make the examiner suspicious.
The Graf Zeppelin issue of the United States is an
odd-sized stamp and is very prone to gum wrinkles, gum bends, or
gum creases. Gum creases can lead to actual creases in the paper
if mishandled. Figure 7 shows two stamps from this issue. The stamp
at right shows traces of a diagonal crease at the left. Only traces
show, though, as the stamp has been regummed to remove the crease.
Normal gum for this issue is on the stamp at left. While this stamp
has been "de-hinged", the regummed stamp has an entirely
different gum. This stamp was regummed by melting the gum and adding
additional gum over the original gum already on the stamp. While
this was done as well as could be, the new gum was dried too quickly
and has the wrong appearance for this issue.
Certain characteristics of gum, both original and new,
are very helpful to know when examining gum. Original gum will often
have color offset ink traces showing on the gum. This is due to the
newly printed sheets being stacked on top of one another while the
ink was still wet. If there are offset ink spots on the stamp and
they are under the gum, one can be pretty sure that the gum is not
original or has been tampered with. Offset on top of the gum would
indicate that the gum is original.
Another thing to look for when examining gum is foreign
matter embedded within the gum itself. Most of the regum jobs are
done by brushing new gum onto the stamp. Brushes lose hairs, so look
for them! Multi-colored gum is another indication of gum manipulation.
If the gum has more than one color in it, the gum cannot be original
unless it has been redistributed.
Regummed stamps often have a "layered" appearance
to the gum. Figure 8 illustrates this type of regumming at right,
with the normal shown at left. There is no pattern to the gum on
the right, and the very faint brush strokes show when examined closely.
This type of gum does not even faintly resemble the properly applied
original gum on the stamp at left. (This illustration also shows
the importance of having a reference or comparison copy.)
One additional factor in detecting gum alteration is
the "curl" of a stamp. This curl can be caused by the weave
of the paper fibers, created during the manufacture of the paper,
or it can be caused by the contracting of the gum applied to the
stamp. All stamps have a curl natural to the issue.
Figure 9 shows a hinged o.g. stamp at left with the
proper curl for the issue, while the stamp at right curls in the
opposite direction. This stamp must be regummed as all original gum
was applied in a similar manner, making different curls impossible.
The hinged stamp was gummed from side to side, while the regummed
stamp was gummed top to bottom.
In Figure 10, the Zeppelin stamp shown at right has
the wrong curl for the issue. The normal curl here is easily seen
on the left stamp. At best, the right stamp has redistributed gum
brushed out side to side which causes the stamp to lie absolutely
flat. (The stamp is the same regummed stamp we examined earlier in
The collector can use these points to protect himself
from the more obviously regummed stamps. When in doubt, a certificate
from a recognized Expert Committee should be obtained. Regumming
is something to be aware of, but certainly not to fear. As in all
aspects of our hobby, knowledge is the best protection