What Security Features Are Used on Blank Check Stock?

With the advent of MICR printing in home and small-business settings, printing your own checks is easier than ever. Once you have the equipment and software necessary to begin printing checks, the only other thing you need is the proper blank check stock. Of course, security is a crucial element of check printing. Understanding the different aspects of check security can aid in making the right decision when purchasing blank checks.
MICR Lines
MICR technology, or Magnetic Ink Character Recognition, is one of the most basic elements of check printing. Unlike standard ink toner, MICR toner uses magnetically-charged ink which can be read by automated equipment. The MICR line is the series of characters printed along the bottom of the check that includes the account number, the routing number and the check number itself.
If you have purchased a high-quality MICR cartridge from a reliable cartridge manufacturer, this so-called "can't read" rate is generally 1% or less, while the rate of character replacement (reading one character as another) is less than 0.00001% or one in one-hundred thousand. Additionally, MICR ink cannot be obscured by stamps or ink from signatures and memo lines. Using a high-quality MICR printer with the appropriate MICR ink cartridge can ensure high levels of integrity for the MICR line.
Additional security features are elements of the check paper itself.
ABA Endorsement
The American Banking Association Endorsement Clause is printed on the back of ABA-endorsed check paper. It includes a warning indicating that the face of the check contains a colored background. The endorsement also includes a facsimile of the check's water mark and ensures that the check was printed using micro-printing.
Watermark Features
Secure check paper is embedded with a watermark. The watermark identifies the check printer, and changes visually when held up to the light. Additionally, it intensifies when held under a black light. It is printed on the back of the check and ensures that the laser check printing meets ANSI and ABA standards. The watermark is a key security feature because it cannot be photocopied, thus ensuring that the check is authentic and original.
Fluorescent Fibers
Like the watermark, fluorescent fibers are embedded in the check. Under black light, the fibers will intensify. Since this property cannot be transferred by a photocopier, the absence of fluorescent fibers indicates that a check is not authentic.
Copier Void Feature
The copier void feature works in the reverse direction as the water mark and fluorescent fibers. Void text, either in paragraph form or in a series of void marks, is printed on the back of the check and is barely visible unless the check is photocopied, in which case the void text becomes clearly visible, indicating that the check is fake. Copier void text may also appear behind the amount and signature lines.
Rainbow Prismatic Features
Laser printed checks are printed with two-color backgrounds. The colors fade in graduated fashion from one to the other, making these checks very difficult to photocopy accurately.
Micro Printing
The micro printing process involves printing text around the edges of the check that can only be read using a microscope. The text is too fine to be read by a photocopier or scanner, or to be printed using a standard printer. The absence or distortion of micro printed text indicates that the check is invalid.
Heat Sensitive Ink
On some laser printed checks, security or patent information can be printed in thermochromatic ink, which changes color when exposed to heat. The heat-sensitive properties of this ink cannot be transferred by a photocopier.