Pardon my ignorance,but why is this cannon smoke BLACK?

[cannonmn]

[MR. GADGET]

I would say that it had a lot of oil or water in the tube. Maybe that was the first shot the tube was put up with motor oil or something to keep down the rust. Or no wads to up the pressure and get a good burn and you are seeing powder just starting to burn mixed in.

What about no smoke?

[John Holland]

Both photo's are of blank fire. It is hard to tell what they were using for a charge.

Just my observations.

JDH
44th NY

[cannonmn]

Someone told me that what the smoke looks like depends on what frame you pick if you are taking the pictures from a video. They also said since video is usually only 30 frames per second, the appearance of the muzzle flash and smoke can change a lot more rapidly than 1/30 second. So if you really want to see what happens, you'd either need some much higher-speed video, or make videos of a number of shots, then look through stop-action of them all to see the variation.