Paper Money Errors: Real Mistakes vs Damage

How a note is printed and where things go wrong

Knowing the order of printing tells you which errors are possible. Notes are printed on large sheets of cotton and linen paper. Higher denominations first get background colors by offset printing. Then the back is printed in green ink by intaglio, a process that leaves the ink slightly raised. Then the sheet dries for days. The black face goes on next and dries again.

After inspection the sheets go through a letterpress that adds the third print: the serial numbers, the Treasury seal, the Federal Reserve seal and the district numbers. Finally the sheets are cut into notes and banded. An error at any one of these stages leaves a signature you can learn to read.

Cutting errors and misaligned notes

When a sheet is fed crooked or the cut is off, you get a note that shows part of the neighboring note along one edge, often with a sliver of its design or margin. Mild versions, with uneven margins or the design touching the edge, are common and bring a small premium at most. Dramatic ones, with a large chunk of the next note showing, are true collector pieces.

Be very careful here. The Bureau sells uncut sheets to the public. Anyone with a paper cutter can make a "cutting error" from one. A genuine misaligned cut usually matches a printing that was also slightly off. Graders compare the plate and position markings. Treat any dramatic ungraded cut error as suspect until an expert has seen it.

Gutter folds and butterfly folds

A gutter fold happens when the paper creases before it goes through a printing press. When the fold is opened afterward, a white unprinted strip crosses the design, usually at an angle. The printing on either side doesn't line up. The crease runs down the middle of the white strip.

A butterfly fold happens when a corner folds over before printing and stays folded through cutting. Open it up and you find an irregular flap sticking out beyond the normal edge, often with part of the design printed on the folded-over paper and a blank patch where it covered the note. Butterfly folds are scarcer and more dramatic than gutter folds.

The test for damage is simple. An ordinary fold made later never has an unprinted strip, because the design was already printed across that paper.

Ink smears, missing prints and offsets

• Ink smears: excess ink spread across part of the note during printing. A genuine smear is the same ink color as the print it came from and often shows the texture of the plate. A smear in a slightly different color or with a felt-tip look is post-production.
• Insufficient ink: part of the design prints faint or blank because the plate was underinked. Fading from sun or washing looks even across the whole note instead.
• Missing third print: no serial numbers or seals. Chemicals can remove ink, so check that the paper texture and color look untouched where the seals should be.
• Third print on the back: the serials and seals printed on the wrong side.
• Inverted third print: seals and serials upside down relative to the face design.
• Offset transfer: a faint mirror image of the face or back on the opposite side, caused by wet ink touching another sheet or a press blanket.

Mismatched serial numbers

Every modern note has two serial numbers on its face. They should match exactly. Sometimes one digit wheel in the numbering head sticks or turns at the wrong moment, so the two numbers differ, usually by one digit. Many people never compare the two, which is why these errors still turn up in circulation.

Check every note you keep. A mismatched serial is a genuine collector premium error. It is also hard to fake without obvious tampering. If both numbers differ in the same place on consecutive notes, you may have a run of them.

How to tell an error from damage

Ask whether the feature could have happened after the note was finished. Tears, holes, pen marks, stains, color shifts, missing corners and folds without a white strip are all things a note can pick up in a wallet or a washing machine. Washing machines also blur ink and soften paper in a way that looks nothing like a printing mistake.

Real errors follow the printing process. Something printed is missing, shifted, doubled or in the wrong place, or the paper was folded before the ink went on. If you can explain a feature by something that happened after cutting, it is damage. Damaged notes are generally face value.

Getting an error confirmed

Dramatic errors are worth having graded by PMG or PCGS Banknote, which both identify errors on their holders. A confirmed error is far easier to sell than one with a story attached. Keep the note flat, don't try to straighten folds and photograph both sides before you send it anywhere.

Frequently asked questions