Selecting the Right Ink Technology for ID Card Printing What You Need to Know

Transcription

1 Selecting the Right Ink Technology for ID Card Printing What You Need to Know Abstract Organizations seeking to produce high resolution identification cards will find an array of card printers from which to choose. Understanding that not all print technologies are equal and the basics of how they work is essential to selecting the right solution. Most identification cards produced today are still personalized using direct-to-card or reverse transfer color resin printing technology. Over the past decade, however, dye sublimation printing has become the leading color application technology of choice. Dye sublimation is a far superior application method than that of color resin. Dye sublimation, when paired with reverse transfer printing technology instead of direct-to-card printing, produces the highest quality images on the most durable cards especially when cards contain embedded technology such as proximity circuits, contact chips, or contactless integrated circuit chips. Reverse transfer dye sublimation is the clear solution of choice for technology-based identification cards. In this paper, you will learn: The differences between today's leading card printing technologies How dye sublimation produces superior quality images Why color resin printing doesn't really produce a true 600 dpi resolution Why reverse transfer printing is ideal for technology cards The value overlaminates play in a card's durability Dye Sublimation Results in Superior Image Quality Dye sublimation printing is a unique process that creates various continuous tone colors within one individual dot or pixel of an image. Dye sublimation printing achieves this through a diffusion process that melds colors together into a smooth, continuous tone, capable of producing over 16.7 million colors. Color resin printing, however, requires groupings of ink dots to signify one single color, lowering the resolution of the image. The illustration on the following page compares the resolution of dye sublimation printing to the resolution of color resin printing. Dye sublimation produces continuous tones that truly achieve the stated printhead resolution of the printer, either 300 or 600 dots-per-inch (dpi).

2 Illustration 1. Dye sublimation printing results in superior resolution. Color resin printing uses yellow, magenta and cyan to create only a limited range of colors when compared to dye sublimation. To create this limited color range, a single color is represented by a grouping of individual colored dots placed adjacent to one another, limiting the color range. Even though resin printing may use a 600 dpi printhead, the actual quality of a color resin printed image remains only 300 dpi. Because the color spectrum is created using a grouping of adjacent dots, which show a granulated image reducing clarity, color resin printers cannot achieve 600 dpi resolution even if using a 600 dpi printhead. Images produced by dye sublimation technology are crisp and of realistic photographic quality. They achieve 600 dpi resolution by fully utilizing the capability of the printhead. The dye sublimation process diffuses the dye, eliminating granulation while producing much greater image clarity. Dye sublimation printing diffuses the dyes together into a single dot on the card surface, producing higher levels of resolution than is possible with resin printers. It is misleading to simply compare the numerical value of the printhead dpi in dye sublimation printing technology to the dpi measurement of a color resin printer. 2

3 Comparing Color Application Technologies: Dye Sublimation Enables More Vibrant Color Color resin printing uses pigment based colors while dye sublimation uses dye-based colors. As shown in the illustration below, pigment inks do not accept light in the same way as dye inks. Dye inks focus light while pigment inks reflect light. The larger size of pigment particles means they tend to scatter the light they reflect, which leads to less vibrant color. Small dye ink particles reflect light evenly for more vibrant color. Because of this, dye-based inks provide superior image color and consequently, better quality images. Illustration 2. Dye-based colors are used in dye-sublimation printing. Pigment-based colors are used in color resin printing. Dye colorants reflect light evenly while pigment particles scatter light. Some colors are not reproducible by color resin technology. Certain graphics, logos and specifically reproducible Pantone colors are not available using color resin printing technologies. Specifically, Kodak Corporation stated that pigmented inks are less suitable for the simulation of Pantone and specialized spot colors, which are especially popular in today's corporate brand palettes. Better colors plus the full gamut of actual colors result in the highest quality print images. Dye sublimation printing technology utilizes color gradation more accurately. Therefore, images are clearer and better defined, allowing images with less contrast to be produced more accurately. This is important when creating small photographic images such as those typically printed onto identification cards. Illustration 3. An example of the superior color and smoother output produced by dye sublimation. 3

4 Dye Sublimation Enhances Eye & Facial Recognition Recognition of a person s eyes is a crucial part of photo identification. Fine detail is more accurately reproduced with dye sublimation printing which gives greater resolution to the eyes, per the illustration below. This enables convenient and accurate visual identification. Illustration 4. The superior eye resolution of dye-sub is crucial for facial recognition. Full color reproduction capability is even more significant when printing a wide range of skin tones. One of the key reasons for using a facial image on a card is easy recognition of that person. Dye sublimation s high color image quality is a crucial factor in getting the desired results of an identification card. Color resin printing technologies cannot match the ability of dye sublimation to accurately reproduce the different skin tones of a diverse population. Options in Card Printing Technologies Now that we've established the benefits of dye sublimation, let us focus on the two primary methods of applying text and images to identification cards using dye sublimation technology direct-to-card and reverse transfer. Direct-to-card (DTC). In direct-to-card printing, images are printed directly to the surface of the card through heat and pressure. The printhead comes into direct contact with the card. This method is less than ideal when producing technology cards because the printhead is coming into direct contact with the uneven surface of the technology-embedded card. Reverse transfer (or Re-transfer). In reverse transfer printing, images are first printed onto a clear film. Through heat and pressure, the film is then fused to the surface of the card. The printhead never comes into direct contact with the card surface. Technology card surface imperfections such as smart chips that are not even with the card surface and ridges caused by internal RFID antennae do not affect the print quality. 4

5 When combined with advanced encoding and lamination technology, the reverse transfer printing process offers the best solution for critical card security applications utilizing technology cards. It should also be noted that cards produced with reverse transfer printing technology are innately more secure and durable than other types of cards because they are inherently tamper-evident if a counterfeiter tries to peel apart the layers, the image essentially destroys itself. They also resist wear and tear by putting a durable layer of reverse transfer film between the card image and the outside world. For enhanced card durability, protective overlaminates provide an ideal solution. For enhanced security, overlaminates can include holographic images and other Visual Security Elements (VSEs) resulting in credentials that are easy to verify but hard to duplicate. Advanced Lamination Technology Improves Card Durability Illustration 5. An overlaminate with holographic images. Reduced Susceptibility to UV Fading. Illustration 5 shows an overlaminate with holographic images that can be laminated to a card using heat and pressure. Overlaminates are used to provide additional durability from abrasion, protection against fading, and provide additional security features such as holograms to the identification card. This technology has been used in conjunction with dye sublimation printing for more than twenty years. One criticism sometimes leveled against reverse transfer dye sublimation printing technology is that the dyes used may fade over several years. Overlaminates solve this problem. To test the susceptibility of reverse image dyes to fading after an overlaminate has been applied, the card and overlaminate are exposed to an accelerated ultraviolet light test to simulate more than five years of strong daylight exposure. The cards are then measured to determine how much fading has occurred. When this accelerated UV test was performed on laminated cards, the fading was imperceptible to the human eye. Superior Adhesion. Another important factor to consider when selecting a printing technology is the adhesion of the laminate to the card. Significant efforts have been made by overlaminate & reverse transfer dye sublimation manufacturers, to ensure that the overlaminates remain securely fastened to the card. In a preliminary test on a limited number of color resin printing technology identification cards, the overlaminate did not remain securely fastened to the identification card. In contrast, overlaminates that had been developed specifically to work with dye sublimation printed cards, did remain securely adhered. With years of testing and field use, overlaminate failure on dye sublimation reverse image transfer cards has proven very unlikely. 5

6 Dye Sublimation Printing Color Resin Printing Dye Sublimation printing impregnates the surface of the card, enabling more secure laminate adhesion. Dyes on reverse transfer film will still leave an image in the card as they diffuse into the cards at the time of transfer. Resin lays on top of the card. Resin color accumulates to 4 layers of resin dots. Prevents laminate from properly adhering to the surface, increasing possibility of card compromise. Illustration 6. Visual explanation of how dye sublimation enables more secure laminate adhesion. Conclusion Reverse transfer dye sublimation printing technology is superior to color resin printing technology and is the clear solution of choice for technology-based identification cards. Not only does reverse dye sublimation printing technology deliver the best photo and text print quality, it ensures that finished credentials are durable and highly secure. For more information on the benefits of reverse transfer dye sublimation technology, read the white paper High Definition Printing for Maximum Security Identification Cards. To learn more about how HID Global card printing solutions can bring security and convenience to your organization using the most advanced printing technology available, visit hidglobal.com/products/cardprinters/fargo/hdp HID Global Corporation/ASSA ABLOY AB. All rights reserved. HID, HID Global, the HID Blue Brick logo, the Chain Design are trademarks or registered trademarks of HID Global or its licensor(s)/supplier(s) in the U.S. and other countries and may not be used without permission. All other trademarks, service marks, and product or service names are trademarks or registered trademarks of their respective owners si-hid-fargo-rev-dye-sub-wp-en PLT