The media are languages just as more normal forms of language - writing and speech - are and just as those more easily recognisable modes of language are governed by rules about use - i.e. grammar - so are the media. The problem tends to be that because the media use spoken and written language as part of their communicative acts the other layers of language can be obscured by our focus on dialogue or print.
Certain parts of the grammars of media are quiet obvious - headlines prioritise, 'talking-heads' such as news presenters are (claim to be) objective narration, bold OR CAPITALISED TEXT is shouting, a film or TV close-up is 'Emphasis!', blue underlining means hypertext link - whereas other parts of these grammars are harder to grasp.
Close-ups are a good example of this as they are the indexical signs of the ideology of individualism; which Althusser showed to be such a key interpellating device. The close-up isolates the important individuals from the mass of characters in a hierarchical representational structure similar to the use of foreground versus background in perspective imagery (photography and so forth) or on the stage.
The final scene of Norma Desmond in Wilder's Sunset Boulevard is a biting commentary on this part of the grammar of cinema. Highlighting the close-up's role in the establishment of leading individuals and the way in which it is a shot reserved for the leading individuals; i.e. for leaders. Sergio Leone also criticised the ideological function of the close-up in his great cycle of westerns by ridiculing it with super tight extra close close-ups (often eyes only) and by utilising it as a tool for creating equality. In Leone's work anybody could get a close-up and this most emphatic of camera shots was not reserved for the leading individuals in the text. Indeed some of the most important sequences in Leone's work are inter-cut tight close ups. In many ways Wilder's criticism of the close up in Sunset Boulevard is far stronger than Leone's because where Leone dismissed the hierarchical function of the close-up Wilder associated it and thus the whole ideology of individualism with a deranged selfish murderous narcissism.
That which is in the seeming proximity of the foreground is granted a greater hierarchical status than those things, persons, characters in the background. That the foreground is an apparent proximity is a key point to remember. Texts are artificial deliberate constructs. Nothing occurs in them by chance (this is why we are told that Hedda Gabler inherited some pistols) and nothing is real. Leading characters and background figures are both 'paper beings' as Barthes describes them in 'Introduction to the Structural Analysis of Narrative' (in Image-Music-Text at p111) so placing them in a hierarchy is a deliberate act based on the deliberate creation of a set of paper beings, paper places, and paper objects to place in this 'paper hierarchy'.
The lesson of the ideological function of the close-up is that just as more normal language is permeated with power so the languages of the media are flooded with power. It is not enough to concern ourselves with the language and grammar of media we must consider the ways in which these languages are used in relations of power and what role these grammars play in the exercise of social power. We must consider the discourse of media; the ways in which the media as language (rather than their content) enact and implement power in society.