There are two kinds of fake stamps: fakes that are created to deceive the US Postal Service versus fakes that are created to deceive stamp collectors. There is a big difference.
Yes, over the years, individuals have created fake stamps that are used to deceive the postal service. They print these stamps in large quantities and sell them to others for less than face value. The fakers pocket the profits. People buying these fakes assume they are real stamps and by buying them below face value, they reduce their postage costs. I’m not going into all of the details here, but numerous stamps have been faked like this over the years. There is plenty of information out there about fakes like these for those interested in learning more.
My focus here are fakes that are created to deceive stamp collectors. Let’s talk about those kinds of fakes.
Some fakes are very easy to create. For example, someone could take a very wide margin copy of Scott #304 (the 5¢ Lincoln issue), trim off the perforations, and turn it into the more valuable imperforate stamp, Scott #315. The amount of effort is minimal and the financial gain, if successful, is large.
Other easy fakes are US coil stamps in the Washington-Franklin head era. Some of these coil stamps are very valuable, such as Scott #388. Some fake coils can be created by taking a genuine imperforate issue stamp and adding fake perforations to it to make it resemble a rare coil. Or sometimes the perforations are removed from a wide margin copy sheet stamp to make it look like a rare coil. With minimal effort and a little manipulation, someone could turn a cheap stamp into a rare coil within minutes.
Let me give you an example of a fake that takes some moderate effort. Someone could take a plate proof of Scott #245 ($5 Columbian) which is worth several hundred dollars as a plate proof. With a little more effort, it’s possible to thin the paper (which is thicker than the issued stamps), add perforations and some gum to create a fake mint copy of Scott #245 which is worth thousands of dollars. All of this isn’t trivial.
Other fakes are even more involved. Two names you may be familiar with are Jean de Sperati and Raoul Ch. de Thuin. There are other counterfeiters who practiced this craft too. These people were masters in their field of creating counterfeit stamps. These two could create fakes that were almost exact replicas of the real items. Their fakes are very dangerous and sometimes even fool stamp experts. Fortunately, others have studied their fakes in detail and published information about how to identify their counterfeits.
This is the other extreme of creating fakes. These fakes took many pain staking hours to create. They had to be printed on just the right paper using just the right ink. Do you think people like Sperati and de Thuin spent their time faking more common and ordinary stamps worth tens of dollars? Or do you think they spent their time faking stamps that were worth hundreds or thousands of dollars?
The lesson to learn here is to understand the context of what it takes to create a fake.
If you’re considering buying a copy of Scott #315, keep in mind that it’s relatively easy to create fakes of this stamp by just removing the perforations from a genuine Scott #304. Because these fakes are so easy to make and with almost no cost, stamps like this need to be studied in more detail because fakes of single stamps are more prevalent.
It takes a moderate amount of effort to create a fake of Scott #245 from a plate proof. Not easy, but it can be done. The financial reward is much higher.
Fakes of difficult stamps are known, such as Scott #2. These were created by master counterfeiters. There is a lot of work involved in making these fakes. The financial reward is very large though.
Sometimes I get beginner type collectors who wonder if their copy of, say, Scott #300 (1¢ Franklin) is a fake. Stamps like these are so common and so cheap that the chances of a copy being a fake is almost zero, unless it was a fake created many years ago to avoid the payment of postage.
A fake of Scott #300 cannot be easily made from another stamp, other than adding perforations to an imperf Scott #314. Since Scott #314 is more valuable than Scott #300, I doubt anyone would purposely destroy a more valuable stamp to create a fake of an inexpensive stamp. No one is going to go to enormous effort to engrave a die to make fake copies of Scott #300. Used copies are so common they are worth almost nothing. Even mint copies are plentiful and only worth a few tens of dollars. The effort involved just isn’t worth the potential reward.
The other thing to remember is that detection of fakes today is far superior than methods used in the past. In the 1940s and 1950s or earlier, expertizing committees were made up of famous/knowledgeable collectors who studied submitted items (called “patients”). They compared the patient to other known genuine or fake copies. They used some perforation gauges and magnifying glasses. Basically these old certificates of authenticity were a collective judgment issued by a group of knowledgeable collectors. Sure, mistakes were made or some well-done fakes could escape the eyes of committee members.
Today, expertizing committees still rely on individual judgments, yes. Those decisions are sometimes backed up by much more science than they have ever been. Some patients go through spectral analysis and other very sophisticated procedures. It’s not at the molecular level yet, but we’re not too far from it. Things like ink composition and paper fibers are much easier to detect.
If Sperati or de Thuin were alive today and trying to make a living at faking stamps, they would have a much more difficult time doing so. Perhaps they wouldn’t even bother faking stamps due to today’s sophisticated techniques employed by the expertizing committees.
Most stamps worth faking are from 1900 or before. Trying to get paper that looks 100+ years old, has certain characteristics, making the ink match, and a whole host of other issues is a huge challenge.
Will someone try to fake, say, British Guiana Scott #13, the famous 1¢ magenta. It’s possible. If a second genuine copy came on the market, it will erase some of the pedigree of the first copy as being the world’s most valuable stamp. A second copy would still be worth a few million in my opinion. However, you know that a second copy of this stamp is going to be analyzed with so much scrutiny and so much detail that it is very unlikely that someone would be able to produce a fake that could pass that many tests.
Forensic science has greatly advanced the authentication of philatelic material. Very valuable items are more susceptible to fakes than more common and inexpensive items.