A convention of film posters would be an image of the main protagonist of the film or an iconic symbol or image from the film for example in Rocky IV Sylvester Stallone is clearly pictured in the centre of the poster. This iconic image from the film drives the narrative forward of the film as he is pictured with the American flag around his shoulders looking victorious. Having Stallone clearly pictured on the poster would enthuse many people to go and see the film and the fact it is the fourth film in the successful rocky saga. Furthermore, Sylvester Stallone is A-list actor by the time of the release of the film adding to the appeal and popularity of the film.
A different example that does not use the protagonist or the main star of the film on the poster would be Saw as the poster includes a sawn of hand which gives the audience information on the genres and the narrative of the film whether the film is suitable for the individual.
A film poster always includes the title of the film, sometimes to drive the narrative forward. The type of font will be relevant to the style of the film for example in the poster for gladiator the font is authentic and relates to the roman era in order for audiences to understand more about the narrative. Another convention would be the taglines included in the film posters. They often play on words and use the rule of three when doing so. An example of a tagline that uses a play on words would be the one used in American Pie (2000) which is 'There's something about your first piece' This tagline cleverly has a double meaning; has a sexual innuendo and refers to actually having a slice of pie. A tagline that includes the rule of three would be from Terminator 2 judgement day (1991) that is 'Same make. Same model. New mission. this uses the rule of three which is physchologically proven that is the most effective way to make people remember the tagline.
The BBFC certificate given to the film normally would be shown on the film poster. The classification of the film would be used in order to inform the audience on the type of content to be expected in the film. The BBFC is also used to help attract their target audience to the film through the film poster.
Another convention included in film posters would be the billing block always seen at the bottom of the poster that is the credits of the film but in short including the names of the main people involved with the making of the film and the main companies that would of produced the film. Along with this technical code the tag-line used 'To find her son, She did what, no one else dared' gives an insight into the narrative in to the film and would attract women in to watching the film as it projects that Angelina Jolie plays a strong, brave women. This would encourage women to be bolder and it also recognizes a real women as it is based on a true story, as it praises the courageous actions of the brave women who did what she could in finding her son and this would encourage women to stand up in what they believe in. The final technical code would be the billing block of changeling makes the poster look more professional and makes the poster come across as being more formal. The 'call to action' gives information on the accessibility of the film such as the dates it is released and the website of the film.
A final convention would be the background images used in film posters often includes the supporting characters or the location where the film is set in order to help drive the narrative forward and the suitability. The main actors name would only be included if the actor is well-known, this can be seen in Changeling where Angelina Jolie's name is printed at the top in order to attract people who would follow her and seeing as she's a respected actor she is worldwide known however in films where the protagonist is quite unknown their name will not be put on and if it is put on the poster it will not be the main emphasis of the poster.