Special effects in your Halloween photography will transform an everyday image into something truly haunting.
Dry ice creates a wonderful fog effect when added to hot water. However, there are some safety concerns with dry ice. Dry ice is not normal ice. Dry ice is frozen carbon dioxide. Do NOT touch dry ice with bare skin. Do NOT eat or drink dry ice. Witches' cauldrons, decorative goblets, and even pumpkins all get even spookier with dry ice fog.
Create ghostly afterimages on your film by using a slow shutter speed and a bit of movement. Each lighting situation is different and you will need to use your camera's lightmeter, along with experimentation, to find the right shutter speed. A rule of thumb for the amount of motion is to have the subject stand still for 2/3 of the time of the exposure. The movement should take about 1/3 of the time. For example, for an 8 second exposure the subject should be still about 5 seconds and move to a second position for 3 seconds.
While in normal situations we usually spend most of our time avoiding film grain and noise, at Halloween its a real bonus. Shooting with very high speed film, or using a digital darkroom program to artificially lighten the scene, creates a wonderful graininess that makes a wonderfully spooky effect on Halloween photos.