CRT & Screen Simulation

A screen look is a pipeline, not a scanline overlay

Most “CRT filters” are a PNG of dark stripes multiplied over the image. That gets you scanlines and nothing else, and it is why they never look like a photograph of a tube. A real display does several things in sequence, and each one changes what the next one receives: the signal is reduced to whatever palette the hardware could address, then broken into the physical subpixels or cells the panel is made of, then spaced by the grid and gutter between those cells, then bloomed by the light the emitters actually throw, and finally bent by the geometry and misconvergence of the optics.

Run those in order and the result behaves correctly — bright areas bloom into their gutters and swallow the mask, dark areas show the structure, and the curvature moves the mask with the surface instead of sliding across it. That ordering is what the Display engine implements.

Shadow mask, aperture grille, slot mask

Every colour CRT needed a physical plate behind the glass to make sure each electron beam only lit its own colour of phosphor, and the three ways of building that plate look completely different.

The shadow mask is a sheet perforated with a triangular array of round holes, with the phosphors laid out in triads behind it. It is the standard consumer tube and its signature is a fine hexagonal dot structure. The aperture grille replaces holes with vertical slits and continuous phosphor stripes — brighter and sharper, because more of the beam gets through, and the approach Sony’s Trinitron made famous. Its unmistakable tell is horizontal: the grille is made of free-hanging vertical wires, so one or two fine horizontal damper wires had to be strung across the screen to stop them vibrating, and they are visible on every real Trinitron. The slot mask is the compromise of the two — rectangular slots in a staggered arrangement, with the brightness advantage of the grille and the mechanical stability of the mask.

Picking the mask is picking which era and which price bracket of television you are imitating, and it changes the image far more than a scanline setting does.

Phosphor, composite and the machines

Monochrome tubes are named by their phosphor. P1 is the green of laboratory instruments and early terminals; P3 is the amber that later terminals moved to because it was easier to read for hours at a time; white is the television phosphor. These are the actual designations, and they carry three quite different moods.

Composite video is the other axis. It carried colour by modulating a subcarrier onto the luminance signal, which is a lossy compromise that produced characteristic artefacts — colour bleeding sideways, dot crawl along vertical edges, and on some machines colour that existed ONLY as an artefact of the encoding. The Apple II is the famous case: it had no colour hardware in any meaningful sense, and its palette was a consequence of how its monochrome output interacted with the NTSC decoder. The Machine control picks which of these you are imitating, alongside the NES and the C64.

Then the flat panels, which fail differently: TFT/LCD has a visible RGB stripe subpixel structure and grey blacks; a projector loses contrast in ambient light and softens at the edges; plasma has its own cell structure and its own bloom; and an LED board is the most extreme reduction of all — discrete emitters with real gutters between them, in amber, red or full RGB.

When you’d reach for it

When the image should look like it was PHOTOGRAPHED OFF a screen rather than displayed on one. That is the useful mental test: if you want the viewer to feel there was a camera pointed at a tube, this is the effect, and the curvature and bloom controls are what sell it.

It is also the most computationally honest way to get a machine-specific look, because the palette reduction and the cell structure are doing the work rather than a colour grade pretending to.

Every option, from the app

Generated from the registry the app publishes, so this list is whatever the current build actually ships — not a copy of it.

Device

Game BoyCRTPhosphorCompositeTFT / LCDLED BoardProjectorPlasma

Model

DMG (green)Pocket (grey)Color (GBC)

Mask

ShadowAperture-grilleSlot

Phosphor

P1 GreenP3 AmberWhite

Machine

NESC64Apple II

LED Colour

AmberRedRGB

Related effects

• Film GrainFilm grain that responds to tone the way emulsion does — peaking in the midtones, on named stocks from Tri-X and HP5 to Portra, Velvia and Cinestill 500T, plus digital sensor noise.
• DitherOrdered dithering: Bayer and blue-noise threshold masks quantised to real machine palettes — Game Boy, PICO-8, CGA, EGA, NES, C64, ZX Spectrum and more.
• DatabendDatamosh-style buffer corruption in six modes — block smears, bitplane damage, bit-shifts, header skew, channel splits and byte swaps.

Open the app to try it; the free effects work with no signup. Open V3KTR · all the FX · how it works