Scanlines

Scanlines refer to horizontal lines or bands visible on the display of electronic screens, particularly in the context of older CRT (cathode-ray tube) monitors, televisions, and early computer displays. They occur due to the way these displays electronically scan and update the image on the screen. The electron gun within a CRT emits a beam that sequentially traces lines from top to bottom, illuminating phosphors to generate the image. This process involves scanning one line at a time, which can introduce visible horizontal lines, especially when the display refresh rate or resolution is not optimized.

In digital displays, especially in emulation and graphics processing, scanlines are often intentionally simulated to evoke a retro aesthetic or to enhance visual authenticity of vintage content. This is achieved by darkening or dimming alternate lines or regions of a picture, mimicking the appearance of old CRT screens.

Scanlines can influence viewer perception by creating a sense of nostalgia or a textured visual experience. They are also used in modern video gaming, digital art, and video production to produce stylistic effects that resemble vintage displays. While real scanlines are primarily a byproduct of CRT technology, digital emulations rely on software techniques to replicate this effect.

The visibility of scanlines depends on factors such as display resolution, refresh rate, and the scaling method used in digital playback. Although largely phased out in favor of flat-panel LCD, OLED, and other modern display technologies, scanlines continue to hold cultural and aesthetic significance within certain media and entertainment contexts.