[Whitebread]

What's the physical difference between the 2 of these?

 

[mikeg]

Unless I misunderstand your question, there is no physical difference between them. CDRs are blank CDs that are used for making copies of CDs.

 

[Whitebread]

Sorry, I wasn't clear.
I meant, what's the chemical differences in the recording substance between CDs and CD-rs? They look different so they must be different.

 

[wallijonn]

www.cdrinfo.com
http://www.cdrfaq.org/

 

[zowie]

Quote:

Originally posted by mikeg Unless I misunderstand your question, there is no physical difference between them. CDRs are blank CDs that are used for making copies of CDs.

No. They're chemically different. CD's don't have the recordable dye and are manufactured through a different process. Did you ever see a blue factory cd?

 

[Whitebread]

Yeah, that's what I meant. Thanks.

 

[monkeymajik]

My first post!

CD's you buy are stamped, CDR's that you can burn at home use a light sensitive dye.

 

[Whitebread]

Are you sure light? If their sensative to light wouldn't that mess up the CD when we open the package???? Do you mean cohearent light??? (Laser)

 

[Cap'n Dan]

Yeah, it's laser... a "burning" laser changes the dye as you record... the reading laser reads it as it would the pits-and-valleys of a normal CD, except the direct/scattering reflection is molecularly-based instead of physically.

 

[Whitebread]

O ok, I understand now, thanks.

 

[Dreamslacker]

Quote:

Originally posted by Whitebread O ok, I understand now, thanks.

And to add, most dyes used in CD-R's are organic. The only exception seems to be the older generation of Metal AZO dye from Mitsubishi/ Verbertim.
This means that they'll breakdown on exposure to UV radiation. Some dyes are highly resistance to this though (Phlatocyanine from Mitsui).

Most CDR's use a silver reflective layer with either cyanine (silver blue) or phlatocyanine (silver-gold). Some of the better and more costly media use gold-gold, gold reflective layer with phatocyanine. Eg. Mitsui Gold, Kodak Ultima Gold, Taiyo Yuden.

 

[Whitebread]

O, ok.