image by rafoto,etc
If you have a lot of light painting to do, you may find that the illuminated areas come out too faint to make an impact. To get around this you'll need to split your scene up into logical areas and take multiple shorter exposures. These can later be combined in a software package like Photoshop or GIMP. To combine your exposures, stack them on top of each other in separate layers and select "Screen" as the blend mode for each.