So I was looking around to find out the difference between DVD+R and DVD-R and found out something even more exciting. Rewind back a few years to when I was still in H.S. I read a newspaper article that said that CDs might actually be very unstable and could fade within a few years. How alarming. Well, FF back to present time.
Apparently CDs actually use organic dye in the bottom part (where the data is). I guess that when you write data to them, depending on what kind of CD it is, it has to absorb a certain wavelength. DVD+Rs are purple (at least, mine are), and will absorb different wavelengths. I don't know which wavelengths. But I do know that short (red) wavelengths shoot out for DVD-Rs.
Anyway, here is some information I found interesting regarding CD-Rs.
There are three basic formulations of dye used in CD-Rs:
1. Cyanine dyes were the earliest ones developed, and their formulation is patented by Taiyo Yuden. Cyanine dyes are mostly green or light blue in color, and are chemically unstable. This makes cyanine discs unsuitable for archival use; they can fade and become unreadable in a few years. Many manufacturers use proprietary chemical additives to make more stable cyanine discs.
2. Azo dye CD-Rs are dark blue in color, and their formulation is patented by Mitsubishi Chemicals. Unlike cyanine, azo dyes are chemically stable, and typically rated with a lifetime of decades.
3. Phthalocyanine dye CD-Rs are usually silver, gold or light green. The patents on pthalocyanine CD-Rs are held by Mitsui and Ciba Specialty Chemicals. These are also chemically stable, and often given a rated lifetime of hundreds of years.
Although the CD-R was initially developed in Japan, most of the production of CD-Rs had moved to Taiwan by 1998. Taiwanese manufacturers supplied more than 70% of the worldwide production volume of 10.5 billion CD-Rs in 2003.
Unfortunately, many manufacturers add additional coloring to disguise their cyanine CD-Rs, so you cannot determine the formulation of a disc based purely on its color. Similarly, a gold reflective layer does not guarantee use of phthalocyanine dye.
There are three basic formulations of dye used in CD-Rs:
1. Cyanine dyes were the earliest ones developed, and their formulation is patented by Taiyo Yuden. Cyanine dyes are mostly green or light blue in color, and are chemically unstable. This makes cyanine discs unsuitable for archival use; they can fade and become unreadable in a few years. Many manufacturers use proprietary chemical additives to make more stable cyanine discs.
2. Azo dye CD-Rs are dark blue in color, and their formulation is patented by Mitsubishi Chemicals. Unlike cyanine, azo dyes are chemically stable, and typically rated with a lifetime of decades.
3. Phthalocyanine dye CD-Rs are usually silver, gold or light green. The patents on pthalocyanine CD-Rs are held by Mitsui and Ciba Specialty Chemicals. These are also chemically stable, and often given a rated lifetime of hundreds of years.
Although the CD-R was initially developed in Japan, most of the production of CD-Rs had moved to Taiwan by 1998. Taiwanese manufacturers supplied more than 70% of the worldwide production volume of 10.5 billion CD-Rs in 2003.
Unfortunately, many manufacturers add additional coloring to disguise their cyanine CD-Rs, so you cannot determine the formulation of a disc based purely on its color. Similarly, a gold reflective layer does not guarantee use of phthalocyanine dye.
Isn't that freaky? I was wondering whilst reading that why some CDs can make the bottom neon orange or something. Well, I'm going to try to do some additional research to see if I can figure out what manufacturers use what, because I don't want my shit to disappear.
1 comment:
This is fascinating! I'm glad you posted it because I had no idea about that stuff. I always wondered why things were different colors. I think I actually might have a blue one, which is bad news.
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