When one shoots a swan, red color will appear.
So I did yesterday night, despite it is a protected animal (at least in the EU).
I used a Baader 7nm Halpha filter 2" in front of a canon EF 85mm f/1.8 squeezed to f/2.5 on a Canon EOS 6 and took 12 frames @ 4 minutes at 6400 ASA.
Darks and flats included.
Here I left the red color as desaturating (making a B/W image from it) loses some detail.
http://skysurfer.eu/skypics1/cyg-halpha-20140828.jpg
And here processed to b&w which succeeded without detail loss: Photoshop => Image => Black&White => Leave only red on:
http://skysurfer.eu/skypics1/large/c...w-20140828.jpg