I am going to be explaining why the following can be considered a limitation to the design of an ident.
Typography
By using typography in an ident, you can tell which ident belongs to which channel. Channels tend to use different typography so the channels all look different because if they all look the same then it will be confusing to tell which channel is which. Typography also gives the channels and their idents a identity so that as soon as you look at it, you know for sure which channel is which. If channels all used the same typography, it would be hard to tell all the channels apart
As you can see from the channels on this on this picture, none of the cannels actually look alike. The typography is different on each of the channels. When you look at channels such as BBC channels, you can see that they are run be the same company so they all have BBC in capital letters, but, BBC one and three are in non capital letters where as BBC two, four and the new are in capitals so people know that they are still different channels and not the same so this could be a bit of a problem because people can the channels mixed up a bit.
Colour
By using colour for idents, it helps the view tell which channel is which. Colours that are for the channel will normally be used in the idents to match the colour of the channels logo. the colour logo is always used in the idents so the audience defiantly know which ident belongs to which channel. If all the channels used the same colour, the Viewers would find it hard to tell them all apart. It can be a problem because their are a few channels that do use the same colours as other channels.
An example of this can be seen in the idents that are used for the channel BBC one. They use the colour red in their idents so that the audience can recognise them because BBC one are known for using the colour red on their channel and in their logo.
Aspect-ratio
All of the high definition idents must be delivered in 16:9 widescreen. This is so that the active picture must fill the 16:9 screen vertically and horizontally without geometric distortion.
'Cinemascope Ratio' letterbox
This is for delivery to the dedicated movie channels or at the discretion of the border-caster, meaning that the programmes may be delivered with an active picture in the cinema ratio of 2.35;1 (21.9) or maybe in 1.85:1, centred vertically between the black bars in a 16:9 frame, filling the width of the actual frame along with no geometric distortion.
Floating Images
This is short sequences of images surrounding the black boards (floating images) may be used for artistic effects. However, that widescreen consumer TV sets operating in auto zoom or auto mode often interpret large black boarders at the top and the bottom of the screen as letterbox so they are likely to enlarge the picture. The resulting zoom can be annoying to the viewers and can undermine the artistic intent. If this is used, the black space around floating images must be consistent across sequences of images.
'Pillarboxed' HD Material
Some "Pillar-boxed" can be acceptable at the border-caster where it has been acquired on a medium that has the capability to be transferred to a legitimate HD resolution. Here is an example, 35mm shot using 4 perf at an aspect ratio narrower than 16:9. The pictures must be centrally framed in a 16:9 raster with no geometric distortion.
'Cinemascope Ratio' letterbox
This is for delivery to the dedicated movie channels or at the discretion of the border-caster, meaning that the programmes may be delivered with an active picture in the cinema ratio of 2.35;1 (21.9) or maybe in 1.85:1, centred vertically between the black bars in a 16:9 frame, filling the width of the actual frame along with no geometric distortion.
Floating Images
This is short sequences of images surrounding the black boards (floating images) may be used for artistic effects. However, that widescreen consumer TV sets operating in auto zoom or auto mode often interpret large black boarders at the top and the bottom of the screen as letterbox so they are likely to enlarge the picture. The resulting zoom can be annoying to the viewers and can undermine the artistic intent. If this is used, the black space around floating images must be consistent across sequences of images.
'Pillarboxed' HD Material
Some "Pillar-boxed" can be acceptable at the border-caster where it has been acquired on a medium that has the capability to be transferred to a legitimate HD resolution. Here is an example, 35mm shot using 4 perf at an aspect ratio narrower than 16:9. The pictures must be centrally framed in a 16:9 raster with no geometric distortion.
Duration
The reason people create Idents that last 3 minutes is so if a channel decide that a show or a film maybe not be on time to show, channels need to make sure that they stick to the time scale that they have so if the channel is a bit late on their showing times, they can put an ident that they can keep up the time scale they already plained and it doesn't get to messed up because of the delay.
The reason for people to not create an ident that only last 30 seconds is because the ident will be pointless to the channel it is being used for. An ident is used as a little time table to let the viewers what is on the channel that day. If the ident is only 30 seconds it won't give the viewers much of an idea what is going on and it won't be enough time to let the viewers know what is coming on and it isn't enough time to let them know what is going to be on once the show or film the viewer wants to see has ended.
