Stack Scanlines, Chroma Bleed & CRT Curve for Old TV

Recreating the tactile, bulbous presence of a 1980s cathode-ray tube television requires more than a simple horizontal line overlay. Genuine old-tube glass possessed physical depth, severe spherical warping, phosphor haloing, and color electron gun misalignment that softened harsh raster boundaries into an authentic analog glow.

The Anatomy of an Authentic Bulbous CRT Display

Modern flat panels distribute pixels evenly across a flat grid, but vintage curved television sets relied on magnetic coils deflecting an electron beam across a thick, spherical glass faceplate. To capture that distinctive look, three visual elements must interact rather than sit in separate, disconnected layers:

• Spherical Tube Curvature: The physical glass was bowed outward toward the viewer. Straight horizontal vectors bowed toward the frame edges, compressing corner detail into a heavy barrel distortion.
• Chroma Bleed & Electron Misalignment: Because the three electron guns (red, green, and blue) rarely hit the phosphor shadow mask in perfect alignment at the tube corners, high-contrast edges bled primary colors outward.
• Phosphor Scanlines: The visible raster lines generated by the sweeping electron beam created dark alternating valleys, breaking up digital sharpness and giving video low-resolution texture.

When these three layers are properly balanced, the screen appears heavy, deep, and physically emissive. You can explore similar retro hardware textures in our cassette futurism CRT aesthetic guide.

Starting Fast with the CRT TV Preset

Rather than assembling the entire stack from zero, open the editor and apply the CRT TV preset. This preset is designed specifically for bulbous screen simulation because it pre-binds spherical tube distortion, beam bloom, chromatic separation, and raster lines into a unified aesthetic.

Instead of presenting a flat, synthetic overlay, the preset automatically weights the CRT curve and glow so that the center of the image retains luminance while the periphery bends away into shadow. It also introduces a touch of analog instability through subtle flicker and vertical roll, simulating an imperfect refresh rate on older NTSC or PAL broadcast receivers.

Fine-Tuning the Knobs to Taste

Depending on whether you want a consumer wood-cabinet living room television, an arcade monitor, or an industrial security display, you can nudge specific parameters away from the default preset baseline:

• Exaggerate the Bubble (CRT Curve + Glow): If your footage needs to look like a small 13-inch portable set or an extreme wide-angle tube, bump this parameter upward. Pushing the knob deeper increases the spherical barrel pinch at the corners and amplifies the soft bloom wrapping around your highlights. If you are simulating a late-era Trinitron with a flatter front face, slide it downward slightly.
• Adjust Phosphor Misalignment (RGB Split): This controls your chroma bleed. Increasing the split drives the red and cyan channels outward from center, simulating aging deflection yokes where the color beams drifted out of registration. Keep it modest if you need text to remain legible; push it higher for distressed broadcast footage.
• Tune Line Pitch (Scanlines): Adjust the slider to match your output resolution. On 1080p and 4K masters, a slightly higher value reinforces the illusion of low line-count analog video. If the image becomes overly dim, compensate by bumping the Brightness or Contrast sliders slightly to keep highlights punching through the raster grid.
• Add Hardware Instability (Flicker & Vertical Roll): Old tubes rarely held completely steady voltage. Nudging the flicker slider introduces the natural 50Hz/60Hz light pulse of cathode phosphorus, while a tiny touch of vertical roll keeps the frame feeling live rather than frozen.

Building the Effect on the Glitchest Timeline

1. Import Your Media: Drag your video clip or still image directly into the browser window. Processing runs entirely on your local GPU via WebCodecs—no files are uploaded to an external server.
2. Apply the Starting Look: Select the CRT TV preset from the preset drawer to drop an initial effect box directly onto your timeline lane.
3. Shape Your Effect Box Boundaries: If you want the old-tube look active across the entire sequence, drag the edges of the effect box to span the full length of the clip. If you want the display to appear as if a monitor suddenly switched on, position a shorter box and drag its left handle inward to create a smooth fade-in.
4. Layer Complementary Boxes on Other Lanes: To simulate sudden signal degradation or tape glitches hitting your CRT tube, drop an additional effect box on a secondary lane above your base CRT layer. Layering boxes across multiple lanes allows the underlying tube geometry to remain consistent while momentary glitch bursts punch over the screen.
5. Export the Master: Once the screen geometry and phosphor bleed match your desired aesthetic, click export to generate a hardware-accelerated MP4, or hit Save Frame to pull a full-resolution PNG still.

For projects requiring complex transitions or localized screen damage, you can combine this bulbous tube setup with masked glitch zones, as detailed in our guide on how to add a CRT effect to video.

The exact settings

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