How To Print A Disc
1. Silk screen
This is still the standard in the industry. Fast, high quality and inexpensive. Can be printed in full process color or premixed, PMS spot colors. The vast majority of all CDs and DVDs are printed with silk screen technology.
2. Offset printing
Offset disc printing is done the same way offset paper printing is done. It does look a little better that silk screen for some artwork. As an example, printing a person's face may come out better and it will be worth the few extra cents per disc that offset may cost. However, most CD duplicators do not own an offset media press costing about $650,000 to $1,200,000.
Thermal transfer printing on discs first appeared in the 90's. It's a printing process similar to that of laser. First it prints onto a ribbon and then the ribbon is transferred to the disc using a heat transfer process. Often this process is used for low volume runs because the transfer process takes up to 80 times longer than Screen or Offset. Also, the process only works in RGB or CMYK. That means you might not be able to perfectly match a specific PMS color. It would be easier to match that PMS color with a pre-mixed ink used in screen or offset printing. Some in the printing industry say that thermal lacks the "pop" of real inks.
The sprayed on ink technology has come a long way since its beginning. Better inks and better "printable surfaces" have improved the process substantially. It is true that you can't print on just any disc surface. Actually, the disc needs to have already been printed with an ink absorbing ink so that the surface will hold the inkjet ink. Unless a clear coating is applied as a separate step after the discs are printed, the discs will still tend to smudge or smear with any type of moisture (be it from your hands or the "sweat" off your soft drink).
5. Light Scribe®
This is a cool, laser etching process that uses a special recorder and software to build a gray scale image into the surface of a special CD. Wait, special recorder, special software and special discs. Sounds expensive! Some have reported that because the laser is used to "draw the picture" as well as burn the data (or audio, or video), the recorders only last 1/3 to 1/2 as long as a normal recorder. That doesn't mean they're not cool, just expensive and the process takes a long time.
6. Printed paper labels
This is an old stand by for home users and those doing small runs. A high quality laser label printed on a high quality laser printer will actually do a pretty good job. The drawbacks are making sure the glues in the label won't eat the lacquer coating on the CD or DVD and that the laser printer is better than the normal "consumer grade" printer. Don't forget the extra labor of applying the labels to the discs when working out your cost comparisons.
7. Sharpie® or some other destructive marker
My personal favorite because it often proves that folks don't know everything about discs. Most markers contain an alcohol based ink. Unknown to most, the alcohol will dissolve the lacquer coating used to protect the reflective layer over time. That in itself isn't a problem but rub that unprotected spot against your clothes, the news paper, virtually anything and you could rub off the metal layer. Now your disc is useless. Best to use a marker on the clear hub of a disc. If you must write on a disc, make sure its been flood coated like the white flood normally found on a "thermal disc".
I'm sure that there's more technology to come but these should take us through the next decade or so.
by Al Foster, VP