In collecting stamps, especially those issued during the classic period prior to 1900, you have to be on the lookout for instances in which stamps have been altered or repaired to increase their value. Some of these alterations or repairs are done so well that special equipment is required to unmask the fraud. In these instances, particularly when a lot of money is at stake, it is important to send the item to an expert committee that has the equipment required to do the job.
However, many of the potential problems involving repairs and other fakery can be detected by with a little experience, a good magnifying glass like this:
a good ultraviolet light like this:
and a good watermark tray and fluid:
The magnifier is a 10x loupe that retracts into the case and has a battery powered light. The UV lamp is a standard 18 inch black light that can be bought at most general housewares or lighting stores like Canadian Tire in Canada. It retails for about $30 or so, and I find works much better than the models sold within the philatelic trade. The watermark try is about $10 and a bottle of watermark fluid is $15-$20.
So, what types of problems are these pieces of equipment used to spot? Generally, any of the following:
- Perforation teeth that have been added or reattached.
- Margins that have been added to imperforate stamps.
- Tabs that have been reattached on the early issues of Israel.
- Thin spots that have been expertly filled with paper pulp or correction fluid.
- Alterations to designs of stamps to create scarce types, such as on early US.
- Re-backing of stamps to create sound stamps or thick paper varieties.
- Cancellations that have been removed - usually pen cancellations.
- Sealed tears.
So, how can you use a magnifier, UV light and watermark tray to detect these things?
It is nearly impossible to re-attach a perforation to the edge of a stamp without leaving a seam where the join is. Examining the perforations closely at the point where the holes are deepest with the magnifying glass will generally be sufficient to reveal whether or not a perforation repair has taken place. Another thing is that you should anticipate where the perforations are most likely to have become damaged, and check those areas carefully. I find that generally, most pulled perforations occur in the top margin of a stamp, and in the corners. It is especially important to check the top perforations near the centre if there is a hinge remnant covering them, as this is any easy way to conceal this type of repair, which will only become apparent when you try to remove the hinge. In fact, carefully examining the surface of the stamp carefully with a magnifying glass will reveal sealed tears, added margins and filled thins fairly easily.
In the case of added margins and alterations to designs, some degree of re-painting of the design takes place, either to create the scarce type, or to restore the frameline where the additional margin has been added. Most of the time the ink will only be an approximate match to the original, and this can be easily seen under a loupe. On the more sophisticated alterations, the UV lamp will do a better job of revealing them, as the new ink will often react differently than the old ink under the light, and this will be easy to see under the UV light.
The UV light is also good for revealing removed cancellations, as they will generally show up quite clearly under the UV lamp, even when they are invisible in ordinary light.
Filled in thins and added margins also often show themselves as areas of discolouration on the back of the stamp. This is particularly prevalent on the pence issues of New Brunswick and Nova Scotia, where the paper was naturally bluish and was prone to thinning. It is quite common to find examples with white spots or whitish bands that run the length of one side. These are generally evidence of repairs in most cases.
Re-backing is one of the more difficult alterations to detect when it has been well executed with a good adhesive that is not water soluble. When water soluble adhesive has been used to stick the new paper to the old paper, soaking in water will generally reveal the repair when the two halves float apart. But if a non-water soluble adhesive is used, this will generally not work. However, using a good water bath or a watermark tray and fluid can still be used to detect possible re-backing by allowing the stamp to sit in the bath and observing whether the solution fully penetrates and soaks the paper. Normally, the paper will become completely saturated so that the stamp becomes a uniform colour in the water. When a stamp has been re-backed though, a tiny air pocket is created in the space between the two halves of the stamp, so that the water will not penetrate evenly. Such stamps will have uneven colouring in the solution, even after they have been in the bath for several hours. This is almost certainly a sign that the stamp has been re-backed.
One of the benefits to collecting modern stamps issued after 1945 is that most of these problems do not exist. Most of the fakery and repairing of stamps is confined to the 19th century and early part of the 20th century. So, this is one factor to consider in deciding what stamps you want to collect.