Common check security features include microprinting, a void pattern that shows on copies, watermarks, chemical protection against alteration, heat-sensitive ink, a padlock icon with a security box, and a MICR line. Together they make checks harder to copy or change. Plain paper has none of them, which is why blank check stock is recommended.
Security features exist because a check is a piece of paper that can be copied, scanned, altered or counterfeited. No single feature stops every fraud, but each one makes a specific trick harder or easier to spot. The exact set varies by manufacturer, so treat this guide as a general tour.
What are the main security features on a check?
| Feature | What it is | What it helps with |
|---|---|---|
| Microprinting | Tiny text, often forming a border or the signature line | Copies and scans blur it into a solid or dotted line |
| Void pattern | A hidden word such as VOID that appears when the check is copied | Photocopied or scanned duplicates |
| Watermark | A faint pattern in or on the paper, seen at an angle or against light | Counterfeit paper |
| Chemical protection | Paper that stains or changes color when touched by solvents | Check washing and ink removal |
| Heat-sensitive ink | Ink that fades or changes color when warmed by rubbing | Copies and counterfeit stock |
| Padlock icon and security box | A small padlock and a list of features, usually on the back | Helps a teller or payee know what to look for |
| MICR line | Routing, account and check numbers in magnetic E-13B characters | Machine reading and some counterfeits |
What is microprinting?
Microprinting is text so small that to the naked eye it looks like a solid line. Under a magnifying glass, you can read words in it. Many checks use microprinting for the signature line or for the border around the check.
Ordinary copiers and scanners cannot reproduce text that small cleanly. A copy usually shows a broken, dotted or blurry line where the original showed crisp tiny letters, which is a quick sign of a duplicate.
What is a void pattern?
A void pattern is a background design that is almost invisible on the original but shows up when the check is photocopied or scanned. The word VOID, COPY or a similar warning appears across the duplicate. That makes it obvious that the copy should not be deposited.
This is different from writing VOID on a check yourself. A void pattern is built into the paper and protects against copies. Writing VOID by hand cancels a check you no longer want paid. See how to void a printed check for that.
What do watermarks and chemical protection do?
A watermark on check stock is a faint image that you can see when you tilt the sheet or hold it up to a light. Scanners and copiers have a hard time reproducing it, so a check printed on photocopy paper often lacks it.
Chemical protection targets check washing, a fraud in which a thief uses household solvents to remove the ink from a stolen check and write a new payee or amount. Protected paper reacts with those chemicals, leaving a stain or color change that points to tampering. It is one reason that stolen checks sometimes look blotchy.
What is heat-sensitive (thermochromic) ink?
Heat-sensitive ink changes color or fades when it warms up. Many checks print a small icon, often the padlock or a stamp-like symbol, in this ink. Rub it with your thumb for a few seconds and the color should change, then return to normal as it cools.
A photocopy normally cannot reproduce this effect. If you accept checks from people you do not know, a quick rub of the icon is a simple authenticity test.
What are the padlock icon and security box wording?
A small padlock icon on the front of a check usually signals that the check includes security features. A short statement, often on the back and often reading something like security features included, lists those features so a teller or payee can check for them.
The wording is a guide for the person looking at the check. It does not add protection by itself, so the feature has to be present in the paper or ink for the statement to mean anything.
What does the MICR line do for security?
The MICR line carries the routing number, account number and check number in a special magnetic font, E-13B. Bank machines read it to sort and post a check, and a line that is missing, smudged or in the wrong spot can make a check get rejected or sent for manual handling.
Magnetic ink is part of why the MICR line is hard to fake with a normal printer. For more detail, see what MICR is and why banks use it.
What does plain paper have, and what is missing?
Plain letter-size paper has no microprinting, void pattern, watermark, chemical protection or heat-sensitive ink. Anyone can copy a plain-paper check on a scanner or a copier, and a changed amount leaves no stain. The tints and designs printed on plain-paper checks are only a look and add no security.
That is fine for some uses. Plain-paper checks are best for deposits you make yourself, including mobile deposit, and whether any bank accepts one is up to the bank. For a check you hand or mail to someone else, the lack of security features is a real risk to you. Read can you print checks on blank paper for more.
Why is blank check stock recommended?
- It is made with security features such as microprinting, a void pattern and chemical protection already in the paper.
- Your software prints the whole check, MICR line included, so nothing about the check is left to a plain sheet.
- Banks and payees recognize the look of the stock, with its perforations and security box.
- It stays a controlled item: because blank stock can be used by a thief, you keep it locked up and track it.
Blank stock is also a fraud risk before it is printed, since it holds the features but no payee or amount. Treat it like cash: store it locked, count it, and shred spoiled sheets. What is blank check stock explains the format, and how to choose the right check paper helps you buy it.
How can you check a check you receive?
- Feel the paper. It should feel like firm bank-grade paper, not thin copy paper.
- Hold it against a light and look for a watermark or fibers in the paper.
- Rub the heat-sensitive icon with your thumb and watch the color change.
- Look for microprinting with a magnifying glass.
- Check that the routing number in the MICR line is a real bank and matches the bank name on the face.
- If anything looks off, call the issuing bank, using a phone number you find yourself, before you deposit.
Check Writer 123 is made by the publisher of this site. For the strongest result, use it with blank check stock, which carries the security features and lets the software print the full check, MICR line included. It also offers plain-paper checks in six designs, which are a look and add no security, and a free watermarked Test Print so you can check alignment before using real stock. See how we protect your account.
Next steps
If you print checks for others, buy blank stock with a solid set of features, store it under lock, and keep a count. To see how security fits in with routine controls, read how to avoid check printing scams and compare paper options in what kind of paper you need to print checks.