How To Find The Grill On Stamps (Beginner’s Guide)

If you have American stamps from the 1860s-1870s, some might be more valuable than you think, all based on something that you may have trouble seeing. Grills are often overlooked by beginner collectors, but knowing where to find stamp grills can help you better understand your collection. 

To find the grill on stamps, you can use a magnifying glass, or carefully rub graphite from a pencil on the grill to better see the impression. You may instead choose to use watermark fluid to make the grill easier to see, or even make an impression of the grill on some aluminum foil.

Of course, identifying which grill is which can be a little tricky. Many grills look similar, and some are hard to see at all. But careful examination can be worth it, as new variants are still being discovered. Below, we go through the process of identifying stamp grills in more detail.

What Is A Grill On A Stamp?

A grill on a stamp is an embossing technique that was used on stamps for a brief time in the United States. Stamps often had their cancellation marks cleaned off, so that they could be reused. Stamp grills were designed to make this harder, if not impossible.

In the mid 1860s, as the Civil War came to a close, the economy was in shambles. Confederate money was now worth less than the paper it was printed on, and people hoarded coins. To solve the lack of circulating money, the government authorized the use of stamps as currency.

Then fears rose of people washing the ink of cancellation off the stamp to reuse it. Smaller, rural post offices might not even have had official cancellation stamping equipment, and would often cancel stamps by hand, making it even easier to remove the ink.

Stamp Grilling Machines

Charles F. Steele, a supervisor at the National Bank Note Company, is credited with the patent for a grilling machine in 1867, though he seems to have been working on the issue since at least 1865.

Running the sheet of stamps through a machine that embossed rows of points into the stamp was designed to weaken the fibers just enough to allow them to absorb more ink. Therefore, any attempt to wash the ink off would just tear the stamp, preventing it from being reused.

While the process was approved for use in 1867, there was no standardization. Several different patterns were used and discarded before the entire process was quietly phased out in the mid 1870s.

Just The US

The National Bank Note Company was replaced as stamp manufacturer by the Continental Bank Note Company, which also produced stamps for Peru that included grills until 1884. These grills were similar to the Z grill (which we’ll discuss shortly), but smaller. No other country is known to have used grills on stamps.

Grilling was an expensive process, and one that risked ruining the stamp completely. In addition, there was little evidence of widespread stamp fraud, making the whole process seemingly unnecessary.

No examples of grilling machines still exist, and there is very little surviving documentation. The grills didn’t even have classifications until philatelist William L. Stevenson developed them in 1916. These classifications are still in use today, even as we have discovered more about the chronology of the grills.

Different Types Of Grills On Stamps

There are 11 different types of grills that were used on American stamps. Each left little pyramid points in a grid on the stamp. The classifications are based on the size of the grid, if the points face up or down, and if the ridges of the pyramids are horizontal or vertical.

A grill that is pointing up was stamped on the back so that the embossing is visible when looking at the front of the stamp. These are frequently easier to see with the naked eye. A, B, and C grills were designed to be points up. It is also believed that these were used on single sheets allowing for fairly uniform patterning.

Some Are Easier To See Than Others

Other grills are designed to be points down or stamped on the face, so that the ridges are visible on the back. These can be harder to see, especially as it seems that the stamps would be embossed up to five sheets at a time. Some would be very distinct while others would have almost no imprint.

The majority of grills were designed so the pyramid points would form vertical ridges. Only the Z grill was designed to form horizontal ridges (again, more on that soon).

A Grills

Size is usually the best indicator of grill type. A grills took up the entire stamp. These were discontinued in favor of grills that made a small grid. These grids can be measured in millimeters or “points.” Most collectors favor one method over the other, but different collectors have different preferences.

B & C Grills

B grills can be identified because they are points up and form a grid of 22 by 18 points that cover approximately 18 by 15 millimeters. Only four known B grill stamps exist. C grills, the other one that is points up, measure about 13 by 16 millimeters, with 16 or 17 points by 18 to 21 points.

D, Z & E Grills

D grills are 12 by 14 millimeters with 15 by 17 or 18 points. Z and E are almost the same size, making it very easy to mistake one for the other. Z grills are about 11 by 14 millimeters with 13 or 14 by 18 points. E grills are 11 by 13 millimeters with 14 by 15 or 17 points.

F & G Grills

F grills are 9 by 13 millimeters with 11 or 12 by 15 or 17 points. G grills are 9.5 millimeter squares with 12 by 11 points, sometimes 11.5. G grills are the only square grids. All others are rectangular.

H, I & J Grills

H grills are 10 by 12 millimeters with 11 to 13 by 14 to 16 points. I grills are 8.5 millimeters by 10 millimeters with 10 or 11 by 10 to 13 points. J grills are 7 by 9.5 millimeters with 10 by 12 points. Few examples of any of these exist.

These last three seem to have been experimental. J grills are not recognized by the Scott catalog and are listed as minor variations of other grills. E and F grills are the most common, though they are sometimes counterfeited as well.

Stamp Grill Chart

Grill TypeMeasurements (mm)PointsPoints Up/Down
ACovers entire stampn/aUp
B18 x 1522 x 18Up
C13 x 1616-17 x 18-21Up
D12 x 1415 x 17-18Down
Z11 x 1413-14 x 18Down
E11 x 1314 x 15-17Down
F9 x 1311-12 x 15-17Down
G9.5 x 9.512 x 11-11.5Down
H10 x 1211-13 x 14-16Down
I8.5 x 1010-11 x 10-13Down
J7 x 9.510 x 12Down

What Do Stamp Grills Look Like?

Stamp grills look like tiny, embossed points. When they are at their most apparent, a grid of small x’s or pyramids is visible. The stamp may seem pebbled, especially with a larger grill or one that is points up.

Other times, the grill may be almost invisible, especially if you are looking at the face of a points down grill. Fortunately, there are some ways to make a grill more visible.

How Do You Identify A Stamp Grill?

To identify a stamp grill, start by making sure you have a good magnifying glass handy. Keep the list of the different grill sizes nearby (such as our list above) or find a chart online. Determine if the grill is points up or points down. If you can see it from the front of the stamp, it’s likely points up, and probably easier to see.

The Graphite Method

If your grill is faint, there a few ways to see the grill better. One is to take a pencil and a piece of scrap paper. Scribble on the paper until you have a lot of graphite dust. Using the tip of your finger, rub the graphite and then lightly touch the grill. The points should pick up enough dust to be visible. Cleaning afterwards is optional, and this technique works best on points down stamps.

Watermark Fluid

Some stamp collectors disagree with this method, believing the carbon weakens the stamp. If you prefer a different technique, others dip the stamp in watermark fluid. Another possibility is to scan the stamp or take a picture and use photo editing software to enlarge it and possibly increase the contrast.

Aluminum Foil

You can also take a clean, unwrinkled piece of aluminum foil, put it to the grill, and lightly rub them to make an impression. Handle the foil carefully as it is easy to ruin your impression.

How To Spot A Counterfeit Stamp Grill

In an ironic if unsurprising twist, the very measures that were meant to prevent stamp fraud have been used to defraud collectors. And there are a lot of counterfeits out there. To try to prevent falling victim to this yourself, there are a few tips to keep in mind. The usual rules apply, of course. Buy from reputable dealers, and if something seems too good to be true, it probably is.

A legitimate grill will be the right measurements and number of points per the chart above. Those points will be perfectly in alignment unless there is a visible reason they wouldn’t be, such as a fold in the paper.

If this is an area in which you wish to specialize, then it would probably be worth it to have a certified set of genuine grill stamps. Ones with small faults can be purchased cheaply and are still usable as reference guides. Due to scarcity, a B grill stamp will be unobtainable for this purpose, but it is also extremely unlikely you will discover a previously unknown B grill stamp!

One final tip for identifying counterfeit stamp grills involves checking for extra gum. As the stamps were grilled after the gum had been applied, extra gum may be a sign that the grill was added much later.

What Is A Z Grill Stamp?

If you have heard anything at all about grills on stamps, you have probably heard about Z grill stamps. The Z grill was the only grill that formed horizontal ridges instead of vertical ones. But the real reason there is so much interest in Z grill stamps is because some of the rarest stamps in the world are Z grills.

The one-cent Z grill stamp has only two known surviving examples and is commonly considered the rarest stamp in the world. This may be inaccurate with the discovery of the 30 cent I grill stamp. Of the two one-cent Z grills, the one privately held was purchased with a trade of four Inverted Jenny stamps, worth approximately $3 million.

Other Interesting Rare Stamp Grills

In addition to the two stamps previously mentioned, the 15 cent Z grill also has only two known surviving examples, as does the 12 cent I grill. The 90 cent I grill has three known examples.

The B grill only has four known examples in total, all being 3 cent stamps. The stamps were apparently used to mail a letter from Mason, Texas, to Germany in May 1869. These stamps were announced to the stamp world in 1969. The cover has since been split, with one being sold off in 1993 for $85,000.

Another was included in the 1998 auction of the Robert Zoellner collection. This auction also contained the 1 cent Z grill. Most recently, it was sold in 2008 for more than a million dollars. The 5 cent A grill has four known surviving copies. The 10 cent Z grill has six known examples. There are 8 examples of the 30 cent A grill stamp. Other rarities may yet be found!

Final Thoughts

To find and identify the grill on stamps, first have a magnifying glass on hand. Then, use some graphite from a pencil, or watermark fluid, or even make an impression on the grill using aluminum foil to make the grill clearer, and then you should be able to measure it or count the number of points.

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