This applies to all stamps and not just US stamps. Some stamps are printed with design errors. Often times, these were overlooked details.
Take, for example, Scott #922 issued for the 75th anniversary of the transcontinental railroad. The US flag on the right side of the stamp is blowing in the opposite direction of the smoke coming out of the steam engine. Obviously, the wind canít be blowing in both directions at the same time. No one knows for sure why it was made this way. My guess is that because the designer included the US flag and had to put it on the rightmost edge of the design, he made the flag blow to the left to squeeze the full flag into the design.
Scott #922 is a true design error. Whatís this error worth? A mint stamp catalogs at the minimum Scott catalog value of 20Ę. Itís a very common stamp that is easily obtainable at a low price.
Most design errors are exactly that: common stamps available at a low price.
Another example is Scott #894 issued for the Pony Express. Only one front leg of the horse is lifted off the ground. When the stamp was issued, horse enthusiasts agreed that the position shown is impossible for a horse. Rumors circulated that the USPOD (as it was known at the time) would withdraw the stamp from sale. People rushed to buy large quantities of it as an ďinvestmentĒ. Well, the USPOD never did retract the stamp and today it too is worth 20Ę as a mint stamp.
Why do I bring this up?
When a design error appears, some are quick to point it out and claim that prices will rise. Unless the issuing postal administration takes the unusual step of recalling that issue, the design error will be in plentiful supply. I would not recommend rushing out to buy huge quantities of design errors as an ďinvestmentĒ. In most cases, the price will not rise and youíre going to be stuck with a lot of ordinary stamps.
A few design errors are more valuable though.
Take, for example, Scott #2870. This pane of stamps for the Legends of the West had the wrong portrait used for Bill Pickett. The picture was actually that of his brother. The error wasnít noticed until after the stamps were printed, but before the stamps were distributed for sale. The USPS decided to capitalize on its mistake by holding a lottery and selling 150,000 panes at face value. The intent was to try and recover the cost of printing these error panes. The USPS went on to reprint the stamp with the correct image of Bill Picket. The correct pane is Scott #2869.
Scott #2870, the design error, sells for about $200 per pane at the time of this writing. Yes, it is valuable. A little bit of the value is because it is a design error and because itís listed in the Scott catalog. Collectors want a copy to complete their collection. However, most of the value comes from its limited sale. Only 150,000 panes were sold, making it a scarce issue. The demand for it is larger than the supply. The price goes up of course.
In 1968, China issued a stamp nicknamed the ďAll China is RedĒ issue. There is a design error. However, the error was only caught after the stamp had been on sale for less than one day. Chinese officials immediately recalled the issue, but not before a few of the stamps had already been sold. This is a rare case of a postal administration recalling a stamp and the design error is quite valuable. Not many of these stamps are known and there is a huge demand for them. Small supply coupled with a huge demand makes for a very large price.
If you are interested, there is a web site devoted to design errors on all stamps, not just US issues. You can find this at http://topicsonstamps.info/errors. Itís maintained by a collector, Ken Polsson. The information is not complete, but it does list many design errors from many countries. Heís also seeking suggestions for other design errors.
If someone touts that a design error is going to be worth a lot of money, donít fall for it. Chances are, it wonít come true. Look, if you wanted to drop a couple of bucks on a design error in the off chance that it may get recalled, thatís up to you. Your investment is small but the risk is high that the stamp will never be recalled. If the stamp isnít recalled, then youíre only out a couple of dollars for your investment. You took a chance and itís not the end of the world. If you bought US stamps, then you can use them up as postage and at least get your money back.
I do not recommend sinking large sums of money into newly reported design errors. Itís rare that a stamp issue is removed from sale. Putting large sums of money into something very risky is not something I would advise you to do. In my opinion, the chances of hitting a huge pay day with a design error are almost zero.
One last comment. To me, design errors are fascinating because they depict things that should not exist. There are several design errors on US stamps. If you included worldwide issues, there are many more. For the collector who canít find anything new to collect, I suggest a collection of design errors. It would make for a very unusual collection. The cost isnít going to be too great since most design errors are inexpensive. And it would be a great conversation piece for both your philatelic and non-philatelic friends. Design errors may be a way to get others interested in the stamp collecting hobby.