The world according to the Blaine Brothers: Luma Key

Let’s move a world away from the blue screen excess of “Sky Captain”. We know it’s not always necessary to key on a colour. Atmospheric elements like smoke, clouds or breath can be achieved by resorting to luma key, in other words keying on the brightness of an image. Here we see how the Blaine Brothers used luma key to create a very chilly atmosphere for their horror movie Nina Forever.

Note there are no gory clips in this interview.

Chris Blaine goes to extraordinary lengths to get the ‘cold breath’ look, and invents a strange variant of Automatic Dialogue Replacement (ADR) – the process in which voice sounds are recorded in post production, but for breath! Note also how in the end he makes it subtle so it’s just adding to the atmosphere instead of drawing attention to itself and exaggerating the moment. Also he mentions he’s got rid of the colour or saturation of the originally shot breath so he doesn’t need to worry about how it might be the wrong colour hue for the shot it is being transplanted into

Can you think of other examples of when you might use luma key? It’s obviously easier than using green or blue, but the disadvantage is it’s sometimes not as precise. With smoke or steam against a black background that’s not an issue. When else might you use this more basic technique? Or could you see Chris’s rather strange technique as being useful to you? Tell us your ideas in the comments below.