There are many different types of ink available that work as security features to help protect sensitive documents from being altered or duplicated. They all add unique features to your document. You will want to select the ones that best fit your needs.
Bleeding ink prints in black but when exposed to any aqueous solution it will produce a red stain. Authenticity of a document can easily be tested without the use of any special agents. User can just wet a finger and run it across the ink to instantly see the affect of the bleeding ink. This ink is only available for use on dry offset printing.
Coin Reactive InksThe image printed from this ink is white or transparent. The image is revealed when the edge of a coin is rubbed over the ink. This provides for immediate verification of document authenticity without the use of any special devices. Coin reactive ink cannot be scanned or copied. This ink is available for use with wet or dry offset and flexographic printing.
Erasable ink is used on the background of a document so that when an attempt is made to erase information, the ink rubs off in that area. The ink will also react in the same manner as solvent/chemical reactive inks do, giving you two security features in one. Erasable inks are used on scenic or pantograph backgrounds on checks and certificates. This ink is not recommended when imprinting a document through a laser printer. The high temperatures associated with laser printers will cause problems within the printer when erasable ink is used. Erasable ink is available for wet or dry offset printing.
Pen Reactive Ink
A transparent ink that becomes visible with the use of a special felt tip pen. The use of the pen is necessary to verify authenticity but can also be used to void a document that is no longer in use. Pen reactive ink is available for dry offset printing.
Heat Reactive – Irreversible
Heat reactive-irreversible ink is colorless when printed. When it is exposed to heat between 185°F (85°C) and 212°F (100°C), sharp color appears and does not disappear once the temperature is lowered. This feature helps protect documents or sealed envelopes from being tampered with by the use of steam or heat. Heat reactive-irreversible ink is only available for use on dry offset presses.
Visible Infrared Inks
Infrared visible inks are available in readable and disappearing ink. When printed they can look the same but when viewed under infrared light, one will be readable and one will disappear. One example of using these two inks as a security feature would be to print a bar code using both inks. Print the actual readable area of the bar code with the infrared readable ink and other areas of the bar code with the infrared disappearing ink but making it look like a regular bar code. When read by a bar code scanner, only the infrared readable is read by the scanner. If a forger tries to duplicate the bar code as it looks on the printed document, using regular inks, the bar code would be rejected when read by the scanner because the scanner would read the entire bar code. Visible infrared ink is available for wet or dry offset printing.
Optically Variable Inks
The color of optically variable ink changes when viewed from different angles. The special effect from this type of ink cannot be duplicated by a scanner or copier. A small area of a document could be printed in this ink to verify authenticity.
Penetrating inks contain a penetrating red dye that goes into the fibers of the paper and will show through to the back of the document. Penetrating inks are commonly used on the arabic and MICR numbering of negotiable documents to deter forgers from trying to scrape the number off from the document. If the number is scraped off the red stain remains on the document. Also, if these documents are duplicated, the reproduction could be easily spotted by checking for the appearance of the red stain on the back of the document. Penetrating inks are available for letter press or wet offset printing.
Photochromic ink can be colored or colorless. When it is exposed to UV light it instantly changes colors. Once the source of UV light is removed it will change back to its original color. The unique properties of photochromic ink cannot be reproduced by a scanner or copier. The authenticity of a document with photochromic ink on it can easily be checked by exposure to sunlight, UV lights or other strong artificial lights. This ink is available in wet or dry offset and flexographic printing.
Solvent/Chemical Reactive Inks
This type ink reacts to solvents or chemicals, such as bleach, alcohol or acetone. The solvents or chemicals are used by a forger to wash away or alter information on a document. When exposed to the solvents or chemicals, these inks will run, change color, or cause a stain to develop. Tampering is easily detected when chemicals or solvents are used on these inks. Solvent/chemical reactive inks are available for wet or dry offset printing.
Thermochromic ink changes color when exposed to heat and then changes back to its original color when cooled. When an area of a document is printed with thermochromic ink, it can easily be tested for authenticity by holding or rubbing the area between fingers to activate the color change. This property cannot be reproduced by a copier. Thermochromic ink is available for wet or dry offset printing and flexographic printing.
Water Fugitive Ink
When water fugitive ink comes in contact with water or any aqueous type of solution, it will run and stain the document. If a forger tries to wash away an image it would be very obvious. Water fugitive ink is available for dry offset printing.
UV Invisible Fluorescent Inks
UV invisible fluorescent ink is transparent white or colorless and can only be detected under ultraviolet light. If a portion of a secure document is printed with this ink, it can be quickly checked for authenticity by viewing under a UV light. UV invisible fluorescent inks cannot be reproduced on a scanner or copier. This ink is available for wet or dry offset, flexographic and gravure printing.