Bobs HCI Work

Posted by on Wednesday 5th November 2003. 1 comments.

Composition (the subject in the frame) – its not just where you put the camera but where you put the characters is also important. Putting an error message in the centre of the screen has the LEAST impact – putting on the sides is more effective.

Framing – this is that the relationship between objects and characters is conveyed by their position in the frame. Dictates how the user perceives the relationship. People often fin the windows full screen option very claustrophobic.
Objects close together are seen as being related. When looking at the horizontal axis, left to right is seen as moving forwards e.g. in video games its very rare to see the characters in a platform game moving right to left. This is possibly because we read left to right. Also in films (especially war films) they always battle left to right. Most people die in films in the lower left hand corner of the screen. Things often enter from the left and move to the right.
The vertical axis, the top of the frame is perceived as more important than the bottom (dominant, powerful, aspiring). So more important information is placed at the top and less important at the bottom i.e. the recycle bin.

Foreground/Background – Background can be used for context – you can use the context of the background to navigate – people map relationships between objects in the background. Dialogue boxes and error messages pop up in the foreground.

Visual Balance – if two people are talking and one exits, the camera will subtly move to restore the visual balance. This aspect is maybe not carried over to HCI as well as some of the other features. However fish eye views emphasis the focus – like on Ron’s Mac.

(Picture)

You can see everything, but the important stuff is highlighted.

Movement (horizontal/vertical) – Moving left to right seems faster, more natural, less threatening and advancing. Right to left is retreating. Moving down seems like falling and a natural movement for deletion. Moving up is progressing.

Movement (foreground/background) – Something moving away from the foreground is seen as leaving. Zooming in draws attention and increases importance. In HCI things come forwards if we need to deal with them.

Movement (camera definitions and effects) – The action leads the camera movements –

Pan – Panning is a stationary camera turning round sideways – this can link two things together.
Tilt – Stationary camera moving from down to up or vice versa – e.g. looking at the building someone is entering.
Tracking – Dolly – Trucking – following a subject of action across a larger space. It follows through different locations.
Zoom – Shows the details of an action within its context. It’s quite subtle and slow for effectiveness. Fast zooms are used more for special effects.
Crane shots – cameras on a crane. The camera is flying across buildings looking down. Often seen at the beginning of movies.
Handheld – You want the viewer to realise the actor is holding the camera like in the Blair Witch Project.

Greater motion leads to more attention.

Lighting and colour
Key lighting – single source usually from the side – gives you lots of shadow
Fill lighting – This is put behind the camera to fill in harsh definitions between light and darkness
Back Lights – used in order to smooth out the edges.
The Contrast Ratio is the relationship between Key and Fill lighting. High key gives an ominous atmospheric feel. Low key is the overall brightness, and this is used in a daytime or family film. The human eye automatically foes to the lightest thing on a screen. You need to consider these lighting effects when considering the type of film.

Production values – This is the superficial gloss or where the money is poured in to make it look good. But if it is a shit film its not going to make the film/interface any better.

Sound and music – Does the sound come from an identifiable source on the screen or is it off the screen – is it related to the action on the screen? Soft, gentle sounds pull the audience into the film, while harsh sounds will push them away. Sounds can imply and define the characteristics of off screen space.

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