Difference between CD-R and CD's bought in shops

[jastock]

Hi.
Can some one tell me the difference between CD-R and those official cd's that you by in shops. When i hold a CD-R up to a light I can see through it. Is that why my DVD player won't play them or is it something else.

[MITSUI_1]

The store bought CDs have a thin layer of metal in them that has actually been "stamped" with little lands and pits to create the zero's and ones that the laser sees. The size of the groves on CD and DVDs are different and require a different frequency laser to see.

CDRs have a reflective layer, and then an opaq "ink" layer. When the CD burner "burns" the disc it heats up the ink and changes its reflective properties in certain places to "simulate" the lands and pits on a regular CD. Some DVD frequency lasers have trouble seeing the simulated lands and pits.

CDRWs use a slightly different process and will sometimes work in players that CDRs cannot see.