Adding Dynamic Lighting Effects with SVG Filters

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SVG filters aren’t just about blurs — they can simulate light, shadow, and depth directly in your code. Using primitives like and, you can create UI elements and visuals that respond to light in a surprisingly realistic way.

Step 1: Create a Lighting Filter

Let’s define a lighting filter that simulates a light source casting soft highlights:

<svg xmlns="http://www.w3.org/2000/svg" style="display: none;">
  <filter id="light-effect" x="-50%" y="-50%" width="200%" height="200%">
    <feDiffuseLighting in="SourceGraphic" lighting-color="white" result="light"
      surfaceScale="5" diffuseConstant="1">
      <feDistantLight azimuth="45" elevation="45" />
    </feDiffuseLighting>
    <feComposite in="SourceGraphic" in2="light" operator="arithmetic"
      k1="0" k2="1" k3="1" k4="0" />
  </filter>
</svg>

This adds soft, directional lighting based on the elevation and azimuth of the light source.

Step 2: Apply the Filter to an SVG Element

You can now apply this filter to an SVG shape like a button or icon:

<svg width="200" height="100">
  <rect x="10" y="10" width="180" height="80" rx="12"
    fill="#4f46e5" filter="url(#light-effect)" />
</svg>

The rectangle now appears lit from a virtual source, with depth and highlight.

Step 3: Customize the Light Source

Want a sharper highlight? Switch from diffuse lighting to specular:

<feSpecularLighting specularExponent="20" surfaceScale="5" lighting-color="white">
  <fePointLight x="150" y="75" z="100" />
</feSpecularLighting>

This gives a more metallic, glossy effect — perfect for UI buttons, knobs, or glassy elements.

✅ Pros and ❌ Cons of SVG Lighting Effects

✅ Pros:

  • 💡 Real-time lighting without raster assets
  • 🌈 Fine control over color, angle, intensity
  • 🧩 Chainable with other filters (like blur or displacement)
  • 📐 Scales perfectly on any screen

❌ Cons:

  • 🧠 More complex than typical CSS effects
  • 🕹️ Animations may require manual control
  • 🕸️ Some effects render slightly differently across browsers

Summary

Lighting with SVG filters gives you powerful visual control — letting you simulate real-world depth, gloss, and glow with mathematical precision. It’s a great technique for UI elements, generative art, or polished visual branding.

📘 Want to dive deeper?

My 16-page PDF guide Crafting Visual Effects with SVG Filters teaches you:

  • How to layer blur, light, and distortion
  • When to use each primitive (and how to combine them)
  • Fully responsive techniques that scale with your layout
    All for just $10.

If you enjoyed this, buy me a coffee ☕ and help support more dev-friendly visual experiments.

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