Blackscreen.onl is a web-based black screen tool designed to help users detect screen issues such as light bleeding, stuck pixels, or display glow. It provides a pure black, fullscreen background ideal for testing monitors, improving contrast during photo viewing, or reducing eye strain in low-light environments. With zero popups and customizable brightness, this tool runs smoothly across all devices and browsers. Whether you're a designer, gamer, or night reader, blackscreen.onl offers a clean, distraction