Why some games have umds without umd letters on it?

[RadekNeli1987]

Some platinum releases have discs with umd letters on them in the middle and some have only middle of discs in white color without it, anyone know why is that?, and what that means?.
Any info will be very helpful.
Thanks in advance for answer.

[LunaMoo]

It means nothing, just like any other decoration on the disc or box. It's like printing "CD" on CD, means nothing, just a reminder of the format name which can be useful when the format's new or hardly differs from other formats, in other cases it's just an extra production cost.

[RadekNeli1987]

Sounds rational, but can anyone confirm or deny this?.
Thanks in advance for answer.

[RadekNeli1987]

Ok I made some research and it's as you said.
I had a theory that later releases of same game version do not have this letters (like they started to produce with them but decided to make without them later to distinguish original from platinum and then all essentials also do not have them) but little big planet (game from 2009) have platinum version with and without them, so it doesn't matter because it's means nothing.