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What alternatives are available to label CD-R and CD-RW discs?
There are several different labeling methods available for CD-R and CD-RW discs ranging from hand writing, to adhesive labels, specialized devices that print directly onto the disc surface and ultimately the various commercial printing solutions. Each option is distinguished by cost, speed and convenience as well as by durability and the visual quality of the result. But keep in mind that applying any kind of label modifies the disc in a significant way. Thus, product warranties can be affected and unforeseen consequences may arise. It is, therefore, advisable to always follow manufacturer directions.
By far the quickest and least expensive way to label a disc is to simply write on its top surface. Using a soft fiber or felt-tipped permanent marker is preferable but be aware that the solvents in some types of inks can migrate through the disc surface and potentially damage the reflective and dye layers beneath. The part of the disc least vulnerable to injury is the center clamping or hub area. Beware ballpoint pens or other sharp writing instruments as they may deform the disc substrate and delaminate the disc layers thereby causing information to become unreadable. Some discs are specially coated to accommodate handwritten labels and even some special markers are available and intended for such use.
A more attractive way to label a disc is to apply an adhesive label. Several manufacturers offer inkjet and laser printer compatible products specifically designed for labeling discs as well as positioning devices to help with centering. Full surface or “donut-style” labels are preferable to partial stickers but be aware that any adhesive label can potentially upset the balance of a disc when playing back, especially at high speeds, causing excessive noise, vibration and data retrieval problems. Heat, humidity, handling and the passage of time can also compromise the stability of adhesive labels causing separation from the disc surface and even interfere with the drive. Sticky labels may not be the best choice when archiving important data as some types of label adhesives can react with and compromise the disc over time. Remember too that, once applied, labels should never be removed or repositioned. Even smoothing air bubbles can concentrate physical stresses in a small area and delaminate the disc.
Specialized Disc Printers
A range of specialized disc printing devices is also available to label discs in larger numbers and for imparting a more polished appearance. Currently, desktop products employing inkjet, thermal transfer and re-transfer technologies are available for directly labeling on the disc surface.
Inkjet printing technology has been available for many years and has proven extremely popular with consumers due to its high quality and cost effectiveness. Inkjet printers function by ejecting liquid ink from a print head onto the surface of a specially coated “inkjet-printable” disc. These special discs have an extra coating, called an Ink Absorption Layer (IAL), which receives the ink from the printer and allows it to stay in place long enough to dissipate its solvents and properly dry. Inkjet printers produce high-resolution full color images but there is a downside in that resulting labels can be smudged by high humidity or damp fingers. Inkjet printed discs should not be stored or shipped in form-fitting soft plastic envelopes as the chemicals used to keep the package materials supple can soften the inks causing the label to stick to the sleeve and potentially delaminate the disc when removed. Using jewelcases or other containers that do not come into direct contact with the printed surface is best.
Unlike inkjet printers which spray liquid ink, thermal transfer printers convey solid pigment from a coated ribbon onto the surface of a disc through a combination of heat and pressure. Typically used to produce monochrome and spot color labels, thermal transfer printing does not require specially coated discs to accept the ink from the printing process. The results are, as well, reasonably durable. However, some disc surfaces give better results than others and offer more protection from potential damage during the printing process. Consequently, discs are available which feature special coatings optimized for thermal transfer printing. For labeling situations where discs share a largely common background appearance but vary slightly from disc to disc or among groups of discs some thermal transfer solutions can align and overprint their output onto partial images already screen printed onto the surface of the disc.
More recently, re-transfer printers have come to market and function by applying heat and pressure to convey solid resins from an ink ribbon to a compliant intermediate film and then to the surface of the disc. Typically re-transfer systems produce photo-realistic color labels which are smooth and highly durable. Only certain types of disc surfaces are suitable for re-transfer printing including those optimized for thermal transfer use as well as some inkjet-printable surfaces and “crystal” protective coatings.
Various methods are used to commercially decorate discs including screen, offset, pad and flexographic printing. These are large-scale industrial processes typically used to label large numbers of discs with the same pattern or in situations when precise color matching is required for critical items such as company logos. In addition to desktop disc labeling, many duplication companies and replicators offer commercial printing services.