I imported my green-screen footage into a new project, and used the Keylight plugin to key out the actor, ready to be comped with other layers. Keylight is very simple to use and it was possible to get good results with only a few tweaks of the settings, such as the clip black and white under 'screen matte'. I then used the pen tool to create a 'garbage matte' that omits any parts of the video that aren't needed.
With my keyed footage ready to be comped, I took some rendered shots of the interior of my spaceship for backplate images.
To make the actor appear to fit his surroundings more, I firstly used 'Tint', a tool that lets you select colours you wish to act as 'black' and 'white' in the video - in this case I used the eyedropper to take a dark and light blue from the rendered backplate. I then lowered the opacity until it was noticeable but not too blue.
I also tweaked the brightness, contrast and saturation to give a more 'cinematic' feel. I heightened the brightness and contrast to make the shadows more dynamic and desaturated the colours slightly to fit the overall mysterious mood of the film.
Finally I added an overlay with a slight gradient to the whole film to emphasise the shadows and highlights and pull the image together more, and added in a hand-painted mist effect (a painting done in Photoshop and added as a low-opacity layer).
Here's a quick look at the process:
The lighting conditions when I filmed the green-screen footage weren't the best - I only used one light to try and create the dark, lit-from-only-one-side look, but this meant the green screen wasn't lit properly and a lot of green tones reflected onto the actor. This is particularly noticeable on the final shot. I did alter the midtones, shadows and highlights using the colour balance tool, but I still don't think it looks quite right, particularly around on the hair. I could probably fix this with more masked colour correcting effects, but I need to move on and start looking at the sound of my film.
I used lens flare to emulate the camera flash, and in the side shot I added a triangular-shaped solid with the layer set to 'screen'. I don't think it looks realistic at all (lens flare in particular has a tendency to look a bit tacky) but I really wasn't sure of an alternate approach.
I used similar colour correcting on the outdoor footage. When adding the spaceship to behind the buildings I thought it looked too flat, so I added a misty effect that I found whilst searching for stock visual effects between the building plate and the ship.
I struggled to find good-quality visual effects for free - the misty one is obviously some sort of dry ice machine and it's very noticeable in some of the outdoor shots, but I'm going to have to leave it.
I really wasn't sure how to go about the abduction shot; I couldn't really think of a method of abduction that would suit my alien, considering he and his environment are more stony and organic rather than technological. I ended up just experimenting with some of the preset effects, in this case 'CC Light Burst' and 'CC Light Rays'. I tried adding in a scatter effect as well, but it ended up spreading too far due the light and looked strange and confetti-like, so I didn't use it.
The shot that I probably edited the most was the shot of the alien, as it had to look as if it was through the perspective of the camera. I created a quick camera interface in Photoshop, added noise, and darkened the animation significantly to make it all appear quite hazy and indistinct until the flash reaches the alien.
I also added the 'wiggler' effect onto the composition to create a shaky, hand-held camera effect that sets it apart from the rest of the film.