When buying a used car, even minor dents hidden under layers of polish or paint can lead to costly repairs if undetected. Professional inspectors and paintless dent repair (PDR) experts rely on a clever, affordable gadget called a dent reflection line board (or PDR line board/reflector board) to reveal these "invisible" imperfections.
The tool is typically a portable board—often striped in bold black-and-white or fluorescent lines, sometimes with LED illumination—that the expert holds or positions near the car's surface. By viewing the reflection of these straight lines in the vehicle's glossy paint, any distortion becomes immediately visible. A perfectly smooth panel reflects the lines as straight and unbroken; even a tiny dent or hail ding causes the lines to warp, dip, or wiggle, highlighting the damage that the naked eye might miss under normal lighting.
This reflection technique exploits how car paint acts like a mirror. It's far more reliable than running your hand over the bodywork or using overhead lights alone, especially on curved panels or dark-colored cars where subtle dents blend in seamlessly. Affordable versions start under $20 online, while pro-grade LED models offer adjustable suction cups for hands-free use.
Mastering this simple yet ingenious tool helps buyers avoid surprises and ensures they're not overpaying for seemingly pristine used vehicles.