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To
preserve optical discs, is a warm environmental condition
the optimal state? |
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My
disc accidentally fell into a pool, can I still use the disc
after I pick it up and wipe off the water on the surface?
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An
optical disc have data previously burnt/recorded into it,
The disc was not used for some time, now the disc is taken
out but the disc is unreadable, is it possible to rescue the
information from the disc? |
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Why
does the recording speed only 8X while I burned a 16X DVD
disc with a 16X DVD recorder? |
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What
causes the print surface of a CD-R to peel-off? How
can this be avoided? |
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How
does one properly store optical discs for prolong usage? |
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Is
it true when the top surface of the CD-R has been damaged
(scratched, peeling, etc.) the disc is useless? Is DVD
disc the same thing? |
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Can
my 8X drive burn a 16X disc? |
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If
you place a sticker, tape, or any form of adhesive on top
of the disc, will it affect the quality of the disc? |
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Is
there really any difference between blank discs from different
manufacturers? |
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My
CD-R media has fingerprints and dust on it. Do I need to clean
it off? |
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Why
are different manufacturers' discs different in color? |
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Why
does it matter what dye is used to make the CD-Recordable? |
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What
are the differences between cyanine, phthalocyanine and azo
dyes? |
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How
does one determine the manufacturer of the disc? |
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If
I bought a HD DVD player, can I use BD discs? Or vice versa? |
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What
is the difference between IS DL Disc and 2P DL Disc? |
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What
is the difference between BD and HD DVD? |
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To
preserve optical discs, is a warm environmental condition
the optimal state? |
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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 s
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.
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My
disc accidentally fell into a pool, can I still use the disc
after I pick it up and wipe off the water
on the surface? |
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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).
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An
optical disc have data previously burnt/recorded into it,
The disc was not used for some time, now the disc is taken
out but the disc is unreadable, is it possible to rescue the
information from the disc? |
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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. |
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Why
does the recording speed only 8X while I burned a 16X DVD
disc with a 16X DVD recorder? |
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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. 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. |
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What
causes the print surface of a CD-R to peel-off? How
can this be avoided? |
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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.
To minimize the effect of the
print surface from peeling off please store the CD-R discs
is a storage device like a jewel case, slim case, or a cover
slip. Also place important data in a controlled environment
by avoiding high temperature and high humidity areas.
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How
does one properly store optical discs for prolong usage? |
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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
(A).Magnets should have no effects on optical discs
(B).X-rays will not harm the optical discs (Airport detectors)
(C).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 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) |
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Is
it true when the top surface of the CD-R has been damaged
(scratched, peeling, etc.) the disc is useless? Is DVD
disc the same thing? |
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Yes, it is true
once the printing surface of the CD-R or CD-RW disc has been
damaged, the disc is pretty much useless because of the disc
structure and the application of the recording materials had
been ruined. CD-R recording material is deposited on the top
portion of the CD substrate which was protected by a thin
layer of protective lacquer coating. Most common damages of
CD-R/CD-RW disc were scratched on the top surface of the disc
which would make the discs useless. Therefore, please take
good care of the CD-R/CD-RW disc on the printing side.
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.
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Can
my 8X drive burn a 16X disc? |
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The burning speed
of the disc is limited by the burning speed of the disc drive;
therefore, an 8X disc drive can and cannot burn a 16X. The
8X drive can burn the 16X disc at an 8X recording speed but
cannot burn the 16X disc at a 16X recording speed.
To be certain what recording speed the drive can utilize,
double check the box of the drive to determine the minimum
and maximum recording speed for each type of disc, or enter
the drive manufacturer’s website to determine the recording
speed limitations of each drive model.
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If
you place a sticker, tape, or any form of adhesive on top
of the disc, will it affect the quality of the disc? |
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Yes, because this
behavior will affect the disc’s dynamic balance. At high-speed
rotation the wobbling of the disc is the greatest thus affecting
the disc read and write qualities and the motor of the disc
drive spindle servo will decay at a faster rate.
● No sticker, tape, or any
form of adhesive on top of the disc.
● Sticker, tape, or any form of adhesive placed on top of
the disc
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Is
there really any difference between blank discs from different
manufacturers? |
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Since all discs
conform to the recording specifications of the "Orange
Book, Part II", all blank discs should work in your recorder
or reader. This, unfortunately, is not always the case. There
are going to be some differences due to the fact that the
discs have been manufactured in different factories using
different equipment. |
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My
CD-R media has fingerprints and dust on it. Do I need to clean
it off? |
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Normally, the read
laser focuses beyond the disc surface so that fingerprints
and minor scratches do no affect the data integrity. A dusty
disc should be blown off so that the dust does not enter the
drive mechanism or wind up on the reader mirror or lens. If
you must wipe the surface, do so with a lens tissue and wipe
gently in a radial direction. |
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Why
are different manufacturers' discs different in color? |
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The color of the
CD-R disc is related to the color of the specific dye that
was used in their recording layer of the disc. This base dye
color is modified when the reflective coating is added. Different
dye and reflective coating combinations can appear green,
blue, or gold. Since the actual operation is only influenced
by the dye used, visual differences between various media
types are irrelevant in terms of any functional impact. |
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Why
does it matter what dye is used to make the CD-Recordable? |
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The dye formulation
used in a CD-R is perhaps the most critical factor in the
disc's performance.
The "Phthalocyanine" dye (thal-o-sy-a-nene)
used in Prodisc discs offer substantial performance advantages
over the "Cyanine" or "Azo" dyes used
by other manufacturers. A "Phthalocyannine" disc
is silver colored with a slight greenish tint. Other manufacturer's
discs come in a variety of shades ranging from blue to green. |
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What
are the differences between cyanine, phthalocyanine and azo
dyes? |
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There are a number
of important recording characteristics and longevity issues associated with each dye and reflectivity coating combination.
Each media manufacturer strives to balance the engineering
characteristics of the dye to insure greater compatibility
with recorders and readers and long archive life. In addition
to cyanine and phthalocyanine, there is also azo dye. Cyanine
dye and its metal-stabilized derivatives were originally used
because the "Orange Book, Part II" referred to the
recording characteristics of cyanine-based dyes in establishing
CD-Recordable standards. Consequently, dyes based on cyanine
tend to have a wide range of acceptable recording power levels
and recording speeds. "Phthalocyanine" dye is a
much more stable dye that is more tolerant when exposed to
light, heat and humidity, which improving after recording
longevity and reliability. Azo dye has been used in other
optical recording media and is now being used in CD-R. These
different dyes, in combination with dye thickness, reflectivity
thickness, materials, and groove structure, are what enhance
or compromise the media recording speed, recording power and
longevity. Phthalocyanine-based discs offer substantial performance
advantages over other discs in three key areas: longevity,
accuracy and compatibility with high-speed CD recorders. |
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How
does one determine the manufacturer of the disc? |
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There 2 methods
of determining the manufacturer of the disc.
Method 1: |
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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. |
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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
DVD Info Pro. This program 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. |
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If
I bought a HD DVD player, can I use BD discs? Or vice versa? |
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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
 
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What
is the difference between IS DL Disc and 2P DL Disc? |
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2P Process
(A) Definition of 2P is Photo Polymerization
(B) 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
(A) Definition of IS is Inverse Stack
(B) 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:
(A) 2P the grooves of both the bottom layer and top layer
coincide with each other
(B) IS the grooves of the top layer is inverted with the
bottom layer
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What
is the difference between BD and HD DVD? |
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BD (Blu-ray Disc)
and HD DVD (High Density DVD) are both blue laser optical
discs (405 nm wavelength optical pick-up head). Each
of the formats is higher in capacity than the current DVD
and is designed for the future recording of High Definition
Television (HDTV). In the market, both are available
for purchase, BD has BD-R (write-once media) and BD-RE (rewritable
media) available, while HD DVD has only HD DVD-R (write-once
media) available with HD DVD-RW and HD DVD-RAM available in
late 2006 and in early 2007, respectively.
•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. |
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