Shades of Halftone: The Art and Science of a Classic Visual Effect

Halftone—the classic dot pattern creating the illusion of continuous tones—is experiencing a renaissance. Here’s how modern shaders are reviving this century-old technique.

The Core Insight

Originally a workaround for limited ink colors in printing, halftone has evolved into an artistic medium. The effect works because our brains perform spatial averaging: past a certain dot radius, we stop seeing individual dots and instead perceive the ratio of “ink” to “empty space” as smooth tones.

This isn’t just nostalgia. Modern tools like Paper, Efecto, and Unicorn Studio are democratizing shader-based halftone effects for designers and developers.

Why This Matters

The beauty of halftone lies in its mathematical simplicity and artistic depth. At its core, it’s just dots on a grid. But the variations are endless:

• Classic halftone: Varying dot sizes based on underlying pixel brightness
• Dots and squares: Inverted patterns where darker pixels yield white dots inside colored areas
• Ring variants: Concentric circles creating a terminal-like aesthetic
• CMYK halftone: Layered cyan, magenta, yellow grids at different angles (the original print technique)

Each variant creates a distinctly different mood while using the same fundamental technique.

Key Takeaways

The Math Behind Halftone:

// Render a dot in a grid cell
vec2 cellUv = fract(vUv * uGridSize);
float dist = length(cellUv - 0.5);
float circle = smoothstep(radius - 0.01, radius + 0.01, dist);

// Luma-based radius (true halftone)
float luma = dot(vec3(0.2126, 0.7152, 0.0722), color.rgb);
float radius = uRadius * (0.1 + luma);

Grid Offset for Higher Density:
Staggering alternate rows (adding 0.5 × cell width to odd rows) allows higher dot density, reducing white space.

The Moiré Problem:
When overlaying multiple halftone grids (like CMYK), rotation matters. Each color channel needs a different angle to minimize interference patterns—typically 15°, 45°, 75°, and 90° for CMY.

Looking Ahead

Halftone is more than a retro effect. It represents a broader trend: constraint-driven design. By imposing rules (dots only, specific grid patterns), we often discover more interesting visuals than unconstrained freedom provides.

For developers, the shader implementations are remarkably approachable. The core technique—distance fields combined with UV tiling—opens the door to countless variations. The next time you need a post-processing effect, consider halftone. It’s simple enough to implement in an afternoon, deep enough to explore for months.

Based on analysis of “Shades of Halftone” by Maxime Heckel