No Mike, these weren't colorised.
They are the actual recorded colours.
The process used was to take 3 identical photos without moving the camera. Each one records different density values by using red, green and blue filtration.
The result is 3 black and white negatives for each scene.
These can then be assembled in photoshop simply as red green and blue channels. This is exactly how film today works in actual fact with multiple black and white recording layers sensitive to different frequencies of light (filters are also employed to clip sensitivity to other colours).
The photographers who made images like these would project the images using a 3 projector setup to overlap filtered positives of the originals.
Because the photos linked to above were a fraction of a second apart, movement is recorded with a rainbow effect and shows up in water and smoke. This is known as the tricolour effect or tricolor filter effect.
If you have a reasonable quality manual digital camera you could try this out.
1. Find a scene with a fountain or water flow.
2. Fix the camera on a tripod.
3. Set the exposure to manual
4. Check your exposure is not over as the highlights are generally most important.
5. Take three identical pictures in succession, being careful not to jog the camera (this is important for alignment later).
6. Open the images in photoshop
7. Select 'channels' from the layers palette
8. Select the green channel and delete its content
9. Select the blue channel and delete its content (Don't delete the layer itself)
9. Select the next image and select 'channels' again
10. Select the green channel, select all and copy its contents
11. Close without saving and return to the first image and paste into the empty green channel
12. Repeat with the third image with the blue channel.
Done.
I think those photoshop steps should work, it's a long time since I last tried it and I don't have the opportunity to check right now.
Let me know
Edit: Misinformation regarding colour film due to lack of sleep
[ 11-22-2001: Message edited by: SunSeeker ]