You have to consider Film Classification when you made a video. Every nation have their own film classification policy.
In British, there’s BBFC (British Board of Film Classification) :
- U
U means Universal. The video with U mark is suitable for everyone. Anyone can see that video. The most basic symbol. - PG
PG stands for Parental Guidance. Anyone can see this but when minors see this, they need confirm or accompany from their parents. It can be violent or lewd in some scenes.
- 12A & 12
It’s almost same – 12A and 12. But in 12A, A stands for Accompany. When the video is 12A, even though he / she is over 12, they need accompany for watch that.
- 15
As you expect, the message is very clear: children only over 15 can watch the video.
- R18
R stands for: Restricted. The video with R18 is only for adults. There’s no way minors can see this videos.
And in Korea, there’s KMRB (Korea Media Rating Board) :
From the left, it’s For All – Above 12 – Above 15 – Only Adults.
The detail shapes or symbols are very different for nations, but the colors are almost same. That’s because every color has feeling and meaning. Green means safe, Red means warning. That’s not official, but everyone thinks like that. That’s why colors are so important.
References;
Website
http://www.bbfc.co.uk/what-classification/r18
http://www.daliboni.or.kr/2013/include/print.popup.jsp?code=NEW20130527184320837