I have written up a science experiment for high school students where I take some photos of a swinging pendulum but it has been pointed out the photos of the pendulum are hard to see and that the images should be improved with a better background or colour.
Unfortunately, it is going to be a bit difficult for me to re-do these images. I was wondering what kind of tricks or software can be used on the photos to improve them (change the background so that the things in the background are not so visible, colour, more contrast and so on).


