Safe Areas refer to the area within your file that is considered ‘safe’, as in it will be definitely visible no matter the viewer’s screen dimensions or size. You should endeavour to make sure everything essential in your ad (including graphics, supers, and action) is within this safe area, else it risks being cut off when actually broadcast.
Please note that Clearcast do not check safe areas from a clearance perspective. When you are creating your final clocked ad and submitting it, it is your responsibility to ensure everything you deem necessary is within the safe area.
The ASA recommends that all ‘essential action’ (i.e anything you definitely want the viewer to see, including graphics and supers) should be within the 16:9 action safe area as below.
16:9 is used by most UK programmes/broadcasters. The 4:3 safe area is required by some broadcasters for end credits or for programmes distributed internationally, so for adverts for UK television, please only use the 16:9 safe areas.