CRT / Old TV
Converter

Seven CRT presets

• NTSC Colour — American colour TV. Full YIQ colour space conversion with chroma compression and a warm phosphor cast.
• PAL Colour — European standard. Slightly cooler, more accurate colour reproduction with subtle chroma smear.
• Soviet SECAM — Heavily desaturated, greenish cast, crushed blacks, high noise, severe barrel distortion, long persistence and burn-in enabled by default.
• P31 Green — Classic green-phosphor terminal (IBM 3270, DEC VT100). Monochrome image luminance-tinted to phosphor green.
• P26 Amber — Amber phosphor (Hercules cards, European terminals). Warmer, more burn-in, higher persistence than P31.
• P4 White — Cool white phosphor (standard TV tubes, early PC monitors). Higher noise, more barrel distortion.
• HDTV 1080i — High-definition interlaced. Even modern CRTs showed combing on fast-motion sports and action content.

Conversion examples

Before

Soviet SECAM

Before

NTSC Colour

Before

P31 Green Phosphor

About interlacing

Interlacing was how CRTs avoided flicker without doubling bandwidth. Instead of drawing all lines top-to-bottom in one pass, an interlaced CRT drew two fields per frame: odd-numbered lines first, then even-numbered lines. At 25 fps (PAL) this meant 50 field refreshes per second — fast enough to appear smooth to the eye.

On still images interlacing is invisible. On moving subjects, the two fields captured slightly different moments in time — producing the characteristic comb effect of horizontal teeth along motion edges. The converter simulates this by dimming alternating scan lines, with higher values adding brightness variation between odd and even rows.

At low values (0–20) it adds a subtle shimmer that makes images feel alive. At high values (60+) the comb structure is clearly visible — wrong on a still image, but authentic on video-sourced content. The Soviet and HDTV 1080i presets have high interlace enabled by default for period-accurate results.