What are the criteria of a disc to be called a blu ray disc?

I just wondering about these blu/blue ray things.



1.What are the criteria of a disc to be called a blu ray disc?

2.Does having blue color on its back side( side with no picture) making its a blue ray?

And last question, does the original blu ray has difference from original DVD/CD? Like graphic or something else?What are the criteria of a disc to be called a blu ray disc?
Bluray discs generally have the Bluray logo on em. theyre not blue, its just called Bluray because the laser used to read/decode them is a bluish/violet color. ("Blue laser ray")

Cds hold around 700mb of data, dvds use 4.7gb-8gb of data and blurays store 20-80Gb of data, thats over 4-20 times what a dvd can store.



most dvds have a blue tint to the back where the data is written but it doesnt mean its a bluray disc, i think they color these blue because they might have some special coating to hold the data better? but blurays can be any color, just the laser used to read them is blue.What are the criteria of a disc to be called a blu ray disc?
Blu-ray disks look almost identical to DVDs or CDs. They are NOT colored blue. The differences are internal to the disk and the BEST way to tell is to look on the disk for the term Blu-ray and logo. It's usually on the lower part of the printed label. See the link for what to look for for various video formats.What are the criteria of a disc to be called a blu ray disc?
Blu Ray disk is an optical storage system, a blu ray disk uses blue laser to store information(hence the name) which allows it to store more information (by increasing the density of info) as compared to a dvd which uses a red laser.