Thanks for all the comments on yesterday's entry, they're much appreciated.
As for how this is done, basically I just followed the instructions on Graham Jeffery's about page:
As far as post-processing goes: both this shot and yesterday's were inverted in Photoshop to give a white background. I guess you could always shoot against a white background in the first place, but I suspect it would be much more difficult to see the smoke.
And that's about it other than to say that yesterday's was colourised and today's was left pretty much as is, other than the application of a rather odd Curve to compensate for the fact that the original was marginally overexposed.
10.11pm on 11/1/06|
EF 17-40 f/4L USM
40mm (64mm equiv.)