Backlit letters bounce light off walls - that's the whole deal with backlit channel letters. Aluminum boxes forming letters, solid fronts on backlit letters, LEDs inside each backlit letter pointing backward at building. Turn on backlit channel letters, light from backlit letters hits wall, bounces back around edges. That's the halo people obsess over with backlit letter signage. Looks pretty damn good when backlit channel letter installation done right with proper backlit letter positioning.

Dark brick or rough concrete behind backlit letters? Backlit letter signage looks weak and disappointing making backlit channel letters waste of money. I've literally walked past buildings where people spent $6,000+ on backlit letters that look pathetic because nobody thought about dark wall killing backlit channel letter effectiveness. Sometimes gotta drop another $1,000 on painted panels behind backlit letters just making backlit channel letters work at all with proper backlit letter reflection.

Thinner aluminum in backlit letters warps from temperature cycling destroying backlit channel letter halos. I've seen backlit letters with thin aluminum get visibly wavy within two years making backlit channel letter halos look uneven and unprofessional. Once aluminum warps in backlit channel letters, you're basically rebuilding entire backlit letter sign from scratch losing backlit letter investment completely.