The lighting in Edwards Scissorhands shows two worlds that are clashing constantly, the normal and the abnormal, reality and fantasy, exterior vs interior beauty. This heightens the modern fairy tale feel of the movie, this small colorful normal town that just happens to have a dimly lit abandoned mansion in the edge of town.

To go along with the modern fairy tale feel, the lighting mimics scenes from movies it is trying to offer the feel of (improperly written sentence), for instance:

here Peg has approached the abandoned mansion at the top of her normal town. Outside it is quite bright but inside

Burton uses sets and lighting that closely resemble that of Dracula. Here we see a darkly lit mansion with just enough light coming in through the windows to cast large shadows and highlight the decrepit nature of the interior, which heavily resembles Jonathan Harker's first entrance to Castle Dracula.

Later Peg finds Edward in the attic hiding in the shadows. The image seems heavily inspired by The Cabinet of Dr. Caligari when his monster first emerges from the shadows, or moreover, the reveal of Frankenstein chained up in the basement. The slow reveal of the creature from the shadows into light heightens he tensions and small amount of terror experienced.

The correlation of these images (Dracula and Frankenstein more than Caligari since it's german, and silent, and most haven't seen it) and the familiar setting and lighting gives this particular film the familiarity of a classic horror film while maintaining the feel of a fairy tale.