Busy skies (M3307868-02541)
More gull trails. Deconstructed video. 30 minutes - that's 45,000 jpegs, though only HD quality. I did drop some frames where birds were too close, or on too confusing a flight path, but there's probably more than 30,000 images in this.
The technique is the opposite of that used for startrails - start with a white background, then add an image on top but only the darkest pixels, then add the next image on top but only the darkest pixels, and repeat. I used a script I knocked up for Imagemagick, a command-line based image processing tool but that's a bit of a heavy tool - you could probably use more friendly editors to batch negative a bunch of images then use a startrail program like Startrax, then negative the result. Oh, I used VirtualDub to extract the individual images from the video, but again that's a bit primitive - there are probably better tools available these days (I just use what I'm used to).
I need to pick some shorter sequences out of this, but otherwise I think I've got everything out of the idea that I can.