CD-R Production proceSS

The major difference in the production process of CD-R (Compact Disc-Recordable) and CD-ROM (Read only), is the Organic DYE used in CD-R.

Unlike an ordinary CD, the CD-R has an organic dye recording layer between the polycarbonate substrate and the light reflective layer. In addition, the polycarbonate substrate is etched with a spiral pre-groove. This pre-groove is used for guiding the laser beam, time measurement and various controls during recording.
The laser beam, modulated by the recording signal, is focused on the groove. The beam heats and melts the recording layer of organic dye on the polycarbonate substrate, forming a series of pits. This pits are physically extremely stable, and are ideal for long-term data storage with the highest degree of reliability.
The color of the CD-R disc is related to the color of the specific dye that was used in the recording layer. This base dye color is modified when the reflective coating (gold or silver) is added. Some of the dye-reflective coating combinations appear green, some appear blue and others appear yellow/gold. Visual differences between various media types are irrelevant from the standpoint of their actual operation. At 780 nm, where CD-R recorders and CD-ROM readers function, the media are, for all intents and purposes, indistinguishable from an optical recording standpoint. They all "look" the same to the devices.

The gold-colored CD-R uses the PhthaloCyanine pigment and a gold reflection layer. As the pigment is transparent, the golden reflection layer shines through the bottom side giving the `golden' look. Compared to the other colored media, the reflection contrast of the golden medium is the highest and the durability of such CD-R's is said to be over 100 years. As the golden medium's reflective property is the highest, if your friends or customers have problems reading data from any other burnt media, try using the gold medium CD-R.

The green CD-R, the cheapest of the three, uses the Cyanine pigment. By itself, the pigment is blue in color, but together with the gold reflective layer, the bottom appears green. However, cyanine's ability to maintain reflectivity is poor giving it a life span of about 10 years. It also delivers the weakest reflection contrasts and thus can cause read errors when run on old CD-ROM drives.
Lately cyanine formula has been altered which results in a much higher life span (20 to 50 years). The gold reflection layer has also been replaced by a silver reflection layer this make the color of the bottom appear blue.

The blue media is made of Azo pigments. Like cyanine, it is blue in color but unlike the green CD-R it uses a silver reflection layer which gives the blue color. Manufacturers claim blue CD-R's are as durable as golden ones.

Einstein-Rare Collection

House of Einstein

Einstein's father

*Was Einstein's Brain Different?*

Of course it was-people's brains are as different as their faces. In his
lifetime many wondered if there was anything especially different in
Einstein's. He insisted that on his death his brain be made available for
research. When Einstein died in 1955, pathologist Thomas Harvey quickly
preserved the brain and made samples and sections. He reported that he could
see nothing unusual. The variations were within the range of normal human
variations. There the matter rested until 1999. Inspecting samples that Harvey
had carefully preserved, Sandra F. Witelson and colleagues discovered that
Einstein's brain lacked a particular small wrinkle (the parietal operculum)
that most people have. Perhaps in compensation, other regions on each side
were a bit enlarged-the inferior parietal lobes. These regions are known to
have something to do with visual imagery and mathematical thinking. Thus
Einstein was apparently better equipped than most people for a certain type
of thinking. Yet others of his day were probably at least as well
equipped-Henri Poincaré and David Hilbert, for example, were formidable
visual and mathematical thinkers, both were on the trail of relativity, yet
Einstein got far ahead of them. What he did with his brain depended on the
nurturing of family and friends, a solid German and Swiss education, and his
own bold personality.

Einstein's mother

Einstein in Berlin with political figures

E = MC^2

School class photograph in Munich , 1889. Einstein is in the front row,
second from right. He did well only in mathematics and in Latin (whose logic

he admired).

A late bloomer:

Even at the age of nine Einstein spoke hesitantly, and his
parents feared that he was below average intelligence. Did he have a
learning or personality disability (such as "Asperger's syndrome," a mild
form of autism)? There is not enough historical evidence to say. Probably
Albert was simply a thoughtful and somewhat shy child. If he had some
difficulties in school, the problem was probably resistance to the
authoritarian German teachers, perhaps compounded by the awkward situation
of a Jewish boy in a Catholic school.

Einstein in a Berlin synagogue in 1930, playing his violin for a charity

concert.