LightScribe (LS) is a labeling system developed by Hewlett Packard (HP).  This unique technology utilizes the laser from the drive and a special printing material applied to the finished disc.  To use this type of disc, after recording the data, eject the disc from the drive and flip it over and place it back into the drive (Use only LS supported drives and discs).  Create a design using a variety of programs available with the drive.  After a couple of seconds-minutes, the image is finished.

LS is a technology that be applied to any optical disc technology.  Currently it is available for CD format and DVD formats.  The next generation formats, HD DVD and BD, will be available soon.  Originally there was only one color available, a light brown/beige color, but now there are other colors available, red, blue, green, yellow, and orange.  The colors refer to the background of the disc not the burned image, printing is only available in black with grayscale.

Example of LightScribe Disc with image

source: http://www.lightscribe.com/images/view_full_champion.jpg

LabelFLash is a labeling system supported by NEC and FujiFilm.  This unique technology utilizes the laser from the drive and special dye layer applied to the dummy side of the DVD disc.  The disc is applied to the drive by flipping the disc over so that the dummy side is facing down and inserted into the drive.  With the support of Nero, the drive can replicate the design and burn an image onto the special dye layer.

Currently there is only a blue-dye background color for the disc and it is only available for DVDR discs.  Also only a hand full of drive makers is supporting the format, NEC and Buffalo

1 Image from “http://www.tomshardware.com/2006/02/14/labelflash_vs_lightscribe_dvd/”

Unfortunately, it is currently impossible for such integration between the two formats.  The HD DVD player cannot play the BD discs and the BD player cannot play HD DVD discs.  Unless the player develops an entirely different pick-up head unit it shows some difficulty to integrate the two different disc technologies.

The difference in the technology is in the development of the disc.  HD DVD discs utilizes a disc structure to current DVD, 0.6 mm + 0.6 mm with an Numerical Aperture (N.A.) = 0.65, while BD format utilizes an entirely new format, 0.1 mm + 1.1 mm with an NA = 0.85.  Although both formats have its advantages and disadvantages, the determinacy of the dominant format is still to early to garner, most forecast a influence by the blue laser disc in around 2010.  Until then, the formats will coexist until one format bows down.

Disc structure differences renders compatibility between the two formats

2P Process

• Definition of 2P is Photo Polymerization

• Photo Polymerization refers to the step where the spacer layer is molded into a grooved surface in order to manufacture the second layer

IS Process

• Definition of IS is Inverse Stack

• The inverse stack refers to the development of the disc when the top layer and the bottom layer are bonded together but the top layer is inverted compared to the bottom layer

Is there a difference?

For the end-user, the difference cannot be seen.The difference is in the structure of the disc:

• 2P the grooves of both the bottom layer and top layer coincide with each other

• IS the grooves of the top layer is inverted with the bottom layer

Table 1.   Information provided by www.bluraydisc.com - 

White Paper – Blu-ray Disc Format – General

Table 2.  Information provided by http://www.hddvdprg.com/hddvd/hddvd_3.html

Other than the difference in the capacity and technical specifications, the disc structures are distinct, especially for BD.  HD DVD utilizes the same structure as current DVD while BD uses a 1.1 mm + 0.1 mm structure.  See below for comparison.

Image 1.  Comparison of (Up) HD DVD disc structure and (Down) BD disc structure.

It depends on the steps of how you deal with after the disc fell into the pool, and which type of disc you used. 

When you begin to dry the disc, please use cloth, or tissue paper. Wipe the disc down from the inner region of the disc towards the outer region of the disc, as shown in the picture below:

These steps can minimize the amount of scratches created upon the disc and increase the chances that the disc can be used again.

The type of disc is also important to the re-use of the disc after falling into the pool. In the market there are discs coated with hard coating (only DVD discs). These hard coated discs prevent scratches upon the reading surface, thus a fall into pool would be harmless to these types of discs (It is not recommended to soak the disc in water for a long period of time).

To prevent any missing data of your disc in the future, please store the discs in the containers (jewel case, slim case, and cake box). Then place these containers in a controlled environment which need to avoid to exposure the disc into high temperatures, humid environments, UV rays, and other contaminants.

There 2 methods of determining the manufacturer of the disc.

Method 1:

Read the stamper number on the disc.  Each company has a distinct stamper number that is unique for each company.  The stamper number should be located near the protruding inner ring on the reading surface, as shown below.  But this method is difficult to determine the manufacturer unless one is familiar with the company’s coding scheme.

Method 2:

There are programs that can be used to read a code placed within the disc itself that distinguishes the manufacturer of the disc. One program is DVDInfo Pro. This programs can allow the end-user to read the MID (Manufacturer Identification). All discs are required to have a MID placed within the disc and this requirements is for both DVD+R/+RW formats and the DVD forum formats. 

The ideal state is to place an optical disc in a vacuum like environment but that is not possible.  Therefore, the optimal environmental state for storage 

1. Lower temperatures 

2. Minimal exposure to water (lower humidity)

3. Reduce exposure to UV light

The recommendations from other sources may vary but the trend should be similar.

http://www.clir.org/PUBS/reports/pub121/table3.jpg

Unfortunately, it is very difficult to rescue information from an unreadable disc. Overtime many discs may change in mechanical characteristics and/or the recording material degrades. 

When writing important information into optical discs store, store the optical discs after writing in a container – jewel case, slim case, etc. – and place in a area with relative low humidity at room temperature and have low exposure to UV light (sunlight).  Under these conditions, most discs can be stored for some time even after many years of storage.

First you should check if the disc is a real 16X disc. If the disc is an 8X disc, then the 16X drive can only burn the disc at a maximum recording speed of 8X.(to determine the disc speed you should check by certain software, i.e. SmartBurn etc)  

If the disc is a 16X DVD disc, the following reasons may have caused the reduction in recording speed:  

(1) The drive does not support the disc manufacturer’s ID code. Every drive maker must place the disc manufacturer information into the drive so that the disc will be read and write correctly. If the drive maker doesn’t input the information into the recorder, the disc may be set to default and will under-utilize the optimum setting.

(2) Compatibility problem. Drive makers must make adjustments to their drive to specific disc manufacturers for the optimal writing speed. It is a good idea to double-check the disc manufacturer for the compatibility results of the discs to various drive makers. 

(3) Inferior product. Some brand may purchase inferior product from disc manufacturer. Usually the inferior disc can be burned but may have down-speed or preservation problem.

The CD-R print surface mainly peels-off due to the environment (high humidity, high temperature, etc.) because of the structure of the disc. Unlike the DVD which has the recording material sandwiched between 2 polycarbonates, the CD-R has the recording material applied to the top surface of the polycarbonate and then protected with a lacquer UV resin. This UV resin provides minimal protection against scratches and the affects of the environment thus causing the print surface to peel-off. 

There are many factors that affects the prolong usage of an optical disc.  The following are some information on the conditions of storage for optical disc.

• Reduce exposure of light (sunlight)

The exposure of sunlight causes heat build-up in the discs’ recording layer thus degrading the disc recording quality.

• Minimize prolong periods in moisture conditions

The polycarbonate of the optical disc is vulnerable to prolong exposure in moisture conditions caused from spills, humid air, or immersion.  The water may be absorbed into the disc and have an affect on the recording materials.  Returning the discs to dry environment will dissipate the moisture absorbed in the disc. Warning:  Water may leave behind contaminants within the discs

• Avoid strong organic solvents

It is highly recommended that all optical discs be not exposed to strong organic solvents such as acetone and benzene since these materials can dissolve polycarbonate.  While limited exposure to mild solvents, like isopropyl alcohol and methanol, are acceptable for cleaning purposes due to the high evaporation of the solvent and the inability to dissolve polycarbonate.

• Effects of magnets, X-rays, and microwaves

1. Magnets should have no effects on optical discs

2. X-rays will not harm the optical discs (Airport detectors)

3. Microwaves should be avoided – it will destroy both the disc and microwave oven

• Storage of the optical disc

It is best to storage an optical disc in a case – preferably a slim case, a jewel case, a amaray case, a snapper case, etc. – the case protects the optical disc from any airborne contaminants and protects the discs from any rapid environmental changes causing stress upon the disc.  For long storage, it is recommended to label the case and not the optical disc since labels may absorb moisture over a long period of time. 

Information provided by NIST (National Institute of Standards and Technology)

As for the DVD disc, this problem will NOT occur because the DVD disc uses different structure. DVD disc is half thick of CDR. In order to get good mechanical character and high performance burning speed, we have to bundle a dummy disc(0.6mm thickness) above the DVD data disc(also 0.6mm). Therefore, we can print (or label) our design on DVD disc's surface (dummy side). By utilizing this method, the recording material of the disc is now sandwiched between 2 protective substrates. So, any damage to the surface of the DVD would not damage the recording material at all.