US Stamps

Tools can help you determine if your stamp is worth expertizing

May 1, 2021, 1 PM

I promised in the last expertizing column (Linn’s, April 28, page 6) that this installment would focus on the tools that expertizers use.

They are, for the most part, tools available to any stamp collector.

For that reason, knowing how to use them — and what to look for — allows you to make some of the judgments expertizers make.

By doing that you can narrow the unknowns, and that can help you decide whether your stamp is likely to get a positive certificate.

I am assuming that you want to get a certificate that says “genuine in all respects.”

Some students of philately also want to have fakes certified as such, and identified as to who the forger might have been.

But either way, if you can pin down some of the properties of your stamp, you can identify stamps that are not likely to pass the process. And that can save you many dollars in submission fees.

In a limited way, learning to make initial assessments means you are taking steps toward becoming your own expert — at least in the realm of United States philately.

Some of the information I’ll share will apply to foreign stamps also, but this column is focused on U.S. material.

You need eight things to be your own expert:

1. Knowledge about what the stamp should look like if it is genuine.

2. Inexpensive varieties of the stamp you are trying to authenticate.

3. Good light.

4. Watermark fluid and a small black tray.

5. A specialist U.S. perforation gauge.

6. A flat/rotary (millimeter) gauge.

7. A 30-power magnifier.

8. Longwave and shortwave ultraviolet lights.

Knowledge about the basic stamps is available most readily from the Scott Specialized Catalogue of United States Stamps and Covers. But there are other resources, some of which were mentioned in the previous expertizing column.

Inexpensive varieties of the stamp in question will not always be available, but when they are, use them.

For example, when assessing if a stamp has been reperforated, compare it to a cheap stamp of the same series that has the same gauge of perforation. Not only should the spacing of the perforations match, but the shape and size of the holes should match as well.

Another example would be finding comparables for the valuable George Washington stamps of 1914 with compound perforations: those perforated gauge 12 by 10, and those perforated gauge 10 by 12 (Scott 423A to 423E). An example of each perforation type is shown in Figure 1 on the 1¢ green stamps.

If you have a stamp that you think might be one of these rarities, find a 1¢ gauge 12 stamp from the same era, and a 1¢ gauge 10, and see if the perforations on these more common stamps match up with the corresponding perforations on the compound perforation stamp you want to authenticate.

If you suspect a stamp has a missing color, putting a normal example side-by-side with the presumptive error will show you where the color should be found.

Good light is also important, such as a 75-watt bulb or better in a nearby lamp, or outside light on a partly cloudy or sunny day. This is especially true for examining color varieties, because the human eye in dim light is not reliable.

Going back to our missing color example, good light and side-by-side comparison are important because on stamps with faked missing colors, the background white in the margins or within designs is often slightly toned by chemicals or even prolonged exposure to the sun.

Watermark fluid and a black tray are needed to detect watermarks on U.S. stamps from the first Bureau issues through the third Bureau issues, and for the $1 Wilson stamp of the 1938 Presidential issue.

Holding a stamp up to the light or against a black background works sometimes, but it is not consistently reliable, especially with yellow and orange stamps. Nor have I had consistently good results with mechanical watermark detectors.

Place the stamp face down in the black tray and pour in a small amount of watermark fluid. To identify a watermark, look at the stamp the moment the fluid touches it, and after it is covered.

This is also a good medium for illuminating flaws such as thins and creases that will show up as darker areas on all stamps whether watermarked or not. It is also helpful in showing where repairs have been made to a damaged stamp.

Standard perforation gauges that measure the number of holes per 2-centimeter space are useful for most stamps, although such gauges are not precise.

In 1965, Richard Kiusalas developed the gauge shown in Figure 2 that measures not just the number of holes, but the precise spacing in thousandths of an inch, so that, for example, there are three gauge 11 measurements for perforations: 11-70, 11-72 and 11-73.

Each U.S. stamp up to that time has a precise perforation, and your patient must match it. The gauge comes with a guide that will tell you what to look for.

Thus, this is an essential tool for recognizing reperforating, and for identifying perforations added to imperforate stamps to create fakes of expensive varieties. Unfortunately, so far as I am aware, the gauge is not currently in production, but specialist U.S. dealers sometimes carry it.

Determining whether a stamp from the third or fourth Bureau issues (regular issues from 1908-38) is flat-plate printed or rotary printed can be the difference between pennies and thousands of dollars.

The millimeter measurements are given in the Scott catalog, and a millimeter gauge (often found as part of perforation gauges) is the obvious way to identify the potentially scarce stamps.

But a faster way of measuring is to take a common 1¢ flat-plate stamp and cut the corners off, as shown in Figure 3. Match that against the stamp you are looking at, and the rotary press printed stamps will be significantly wider or taller than the flat-plate product. If you think it is rotary, use the millimeter gauge to confirm it.

Ten-power magnifiers are frequently seen in the hands of stamp collectors, but 30-power magnifiers are often available inexpensively from photo supply stores. An Internet search can also turn up places to purchase them.

This tool is essential for the expertizer, especially when looking at presumptive missing colors, regumming or missing perforations.

The 30-power magnification lets you see the individual dots of photogravure printing.

Since a missing color must be missing 100 percent to be designated as an error, if you see even a couple of dots of color under 30-power magnification that you can’t see with the unaided eye, it will not pass.

The same is true of imperforate errors. A pin impression under 30-power magnification will disqualify it.

The 30-power magnification is also important when looking at die types, examining double prints against kiss prints, and checking overprints, such as those on the Kansas-Nebraska issues of 1929.

Shortwave and longwave ultraviolet lamps are available as a single piece of equipment or less expensively as separates.

By comparing a stamp being examined with normal examples, these lamps can help you determine if tagging is missing, or has been altered. If altered tagging is detected, that can be a prime lead for identifying a stamp that has had its printed colors altered.

This is a very short course, but it should provide you with some helpful hints for examining your own stamps.

The bottom line is that through a combination of self-education and the use of tools available to you, you can often determine whether you have something that it will pay you to have expertized.

Your questions and observations about expertizing are welcome, especially on matters you would like to see addressed as this series progresses.

Send me a note via e-mail at, or write to me, John Hotchner, Box 1125, Falls Church, VA 22041.

Cartoon winner

For the first time in the long history of the Linn’s cartoon caption contest, more entries were sent by e-mail than by postcard. Either method works for me, but e-mailers too often forget to add their postal mailing address, which I need to write up the winners, and which Linn’s uses to provide winners with their prizes.

The stamp used for the April contest was the 2006 39¢ Benjamin Franklin stamp in Figure 4, which makes the following entry from William David Webb of Jenkintown, Pa., especially appropriate: “This electricity I discovered might actually deliver messages — I could call it e-mail.”

The technology divide between the 1700s and today was evident in many of the entries.

Another that struck me is “What are these numbers that are being called ZIP codes?” sent by David Kloha of Carleton, Mich.

The current plight of the Postal Service was the subject of several entries. From these, two caught the problem perfectly.

The first from Edgar Dunlap of Gainesville, Ga., is “Poor Richard! Now there’s someone who can identify with today’s Postal Service!”

The second is from Ira Cotton of Naples, Fla., who takes a more proactive approach with, “If only I could think of some collectible that people would buy to help reduce our postal deficit!”

Surprisingly, there were very few nonphilatelic entries for this contest, and so many great philatelic lines, that it is only fair that both winners come from the latter group.

In Figure 4, Joel Meyerson of Annandale, Va., has Franklin considering a futuristic concept that would come to be in 1847.

The other winner, from Charles Chiaramonte of Valley Stream, N.Y., transplants one Revolutionary War tale into postal terms, using the form of a letter: “Dear Mr. Franklin, please confirm Mr. Revere’s proclamation of postal rates as: 1 (cent) if by land and 2 (cents) if by sea.”

Both winners will receive Linn’s Stamp Identifier published by Amos Hobby Publishing, or a 13-week subscription to Linn’s (a new subscription or an extension). The book has a retail value of $12.99.

Here are a few of the runners-up:

“Let’s see: kite, string, key … lightning, electricity, quick communications … no paper, no job. Hmmm — maybe I don’t want to go kite flying after all!” by Phil Fondale of Pioneer, Calif.

“Profitability, profitability … If only they had listened to me!” sent by Bob Finck from Fenton, Mo.

“My to-do list: Found new nation, check; Invent bifocals, check; Fix the postal system … oops,” by J. Krafty of Mechanicsburg, Pa.

“Bet you can’t say this three time fast: ‘Franklin’s frank is B. Free Franklin,’” from Steve Kotler of San Francisco, Calif.

“Thinking ahead, they could save expenses by deleting these holes and allowing the public to cut their stamps apart,” by Michael Moticha of Apple Valley, Calif.

Thanks and a tip of the hat to all who entered.

The next cartoon caption contest will be announced in the June 9 Linn’s.