Thursday, December 17, 2009

Using Stills in Video

In videos we often find one or more stills interspersed with video footage. In some cases, such as historical photos or portraits of people, this can be acceptable. However more often than not, a single contemporary still of say a building in the midst of a travelogue can be very jarring.

While the use of a “Ken Burns” effect to animate the still (pan and/or zoom) may help to minimise this problem, the image usually remains recognisable as a still. Here are two techniques that might just trick most people into seeing footage when they are in fact looking at a still. These techniques work best where the subject of the still is outdoors and static (eg a building or landscape) without any apparent “frozen action”.
They also work better when used in a short rather than long clip.

The techniques are based on using Premiere Pro and Photoshop Elements, but should work equally as well in programs with similar capacities.

The first technique involves superimposing footage of moving foliage to one upper corner of the frame.

Shoot some overhanging foliage (with some movement) against a uniformly coloured sky. Frame the shot so that the foliage appears in only one or other upper corner of the frame.
In Premier, Place the foliage footage on track 2 of the timeline.
If there are variations in the sky behind the foliage (eg clouds), or any other objects appear on the screen, use a four (or more) point garbage matte to isolate the foliage and the immediate area around it.
Open the RGB Difference Key.
Place the eye-dropper over the sky area next to the foliage and click.
Slide the Similarity Slider back until the sky disappears and only the foliage is visible.
Place the main still image on Track one and scale to fit.

In playing the clip, the still should be framed by the slightly moving foliage.

The second technique involves replacing the still sky with a sky with moving clouds.

Take a photograph of the sky (with clouds) and save to the computer.
Open the main still image in Photoshop.
Using the selection tools, select and isolate the sky.*
Click on Select/Inverse to select the non-sky area of the image.
Copy the image.
Open a new blank file (with a transparent background).
Paste the image. The image will appear with the sky area “chequer-boarded” out.
Save the image as a Photoshop file.
In Premier import this file and place on track 2 of the timeline, and scale to fit.
Import the sky image and place on track 1 of the timeline.
Scale the image to be about 15% larger than the screen.
Using keyframes, animate the image so that it slowly moves horizontally across the screen.
If necessary, adjust the colour and lighting of one or both tracks so that they “match”.

The main still image should appear with moving clouds above/behind it

*Some knowledge of selection techniques in Photoshop is assumed.

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