CRT Displays, Scanlines & Refresh Rates
CRT displays use electron beams to illuminate phosphor dots on a screen, creating images line by line, known as scanlines. These scanlines are visible as faint horizontal lines, especially in older or lower-resolution displays. Refresh rates indicate how often the image is redrawn per second, measured in hertz (Hz). Higher refresh rates reduce flicker and provide smoother visuals, while lower rates can cause noticeable flickering and eye strain.
CRT Displays, Scanlines & Refresh Rates
CRT displays use electron beams to illuminate phosphor dots on a screen, creating images line by line, known as scanlines. These scanlines are visible as faint horizontal lines, especially in older or lower-resolution displays. Refresh rates indicate how often the image is redrawn per second, measured in hertz (Hz). Higher refresh rates reduce flicker and provide smoother visuals, while lower rates can cause noticeable flickering and eye strain.
💡 Key Takeaways
- Understand how CRTs render images with electron beams that scan the screen line by line (raster scanning) and light phosphor dots.
- Recognize what scanlines are and why they appear as faint horizontal lines on older or lower-resolution displays.
- Learn what a refresh rate is (how many times per second the image is redrawn) and how it affects flicker and the feel of retro gameplay.
- Discuss how CRT visuals influence retro gaming aesthetics and why emulators sometimes simulate scanlines and glow to recreate the classic look.
❓ Frequently Asked Questions
What is a CRT display and how does it render images?
A CRT uses an electron gun to shoot electrons onto a phosphor-coated screen. It scans the image line by line from top to bottom, lighting phosphor dots to form each frame; colors come from red/green/blue phosphors and a color mask.
What are scanlines and why do they appear on CRTs?
Scanlines are the visible horizontal lines created by the line-by-line drawing process. On older or lower-resolution CRTs, the gaps between lines appear as faint lines across the image.
What is a refresh rate and why does it matter for retro games?
The refresh rate is how many times per second the image is redrawn (measured in Hz). A higher rate reduces flicker and smooths motion; retro systems in NTSC regions usually run around 60 Hz, while PAL regions run around 50 Hz.
How do CRT scanlines and resolution affect the look of retro games?
Retro games often render at lower resolutions that match CRT scanlines, producing a distinctive look with crisp lines and phosphor glow. The overall appearance is shaped by line-by-line rendering and the monitor’s persistence.