Your textures look perfect in the Editor. Smooth gradients. Clean lighting. Then you build to Android or iOS and everything looks worse. Gradients show visible lines. Shadows look blocky. Colors shift slightly.

This is often called a Unity texture compression bug. In reality, it is almost always caused by aggressive mobile compression formats.

Mobile GPUs use specific compression algorithms that reduce texture size dramatically. The tradeoff is visible artifacts if settings are not chosen carefully.

Why This Happens on Mobile Only

In the Editor, textures are often displayed uncompressed or using desktop compression formats.

On mobile builds, Unity converts textures to platform-specific formats such as:

• ETC2 (Android)
• ASTC (Android and iOS)
• PVRTC (older iOS devices)

These formats reduce memory usage but can introduce color banding and block artifacts, especially in gradients.

What Is Color Banding?

Color banding appears when smooth gradients become segmented into visible steps.

This happens because compressed formats reduce color precision to save space.

Textures with subtle lighting, fog, or UI gradients are especially vulnerable.

Step 1: Check Platform Override Settings

Select your texture and scroll to Platform Settings.

Enable:

• Override for Android or iOS

Now inspect:

• Compression format
• Compression quality
• Max Size

The default format is not always ideal for your texture type.

Step 2: Use ASTC for Higher Quality

If your target devices support it, ASTC offers better quality at similar sizes.

Instead of ETC2, try:

• ASTC 6×6 or 4×4

Lower block size (like 4×4) gives better quality but increases memory usage.

Test visually on a real device.

Step 3: Increase Compression Quality

In texture settings, change Compression Quality from Normal to High.

This slightly increases build time but improves visual output.

Step 4: Disable Compression for Critical Textures

For UI gradients or sky backgrounds, compression may not be acceptable.

Set:

• Compression: None

Only do this for small textures. Disabling compression on large textures increases memory usage significantly.

Step 5: Avoid 16-bit Source Images

If your original texture is low bit depth, compression artifacts become worse.

Use high-quality source PNG files when possible.

Step 6: Watch for sRGB and Color Space Issues

If your project uses Linear color space, compression artifacts may appear more visible.

Check:

• Project Settings → Player → Color Space

Linear lighting increases precision requirements for gradients.

Step 7: Reduce Gradient Dependency

Very subtle gradients are the hardest for compression algorithms.

Possible design solutions:

• Add subtle noise to gradients
• Break large gradients into smaller sections
• Use shader-based gradients instead of texture gradients

Adding small dithering noise can hide banding effectively.

Common Scenario: UI Looks Fine in Editor but Broken in Build

This is extremely common because the Editor preview does not always show final mobile compression.

Always test compression visually on a real device before release.

Memory vs Quality Tradeoff

Mobile optimization is always a balance:

• Smaller size → more compression → more artifacts
• Higher quality → larger memory usage

There is no universal perfect setting. It depends on your target device range.

Quick Debug Checklist

• Enable platform override
• Test ASTC instead of ETC2
• Increase compression quality
• Disable compression for critical UI textures
• Add subtle noise to gradients
• Test on real hardware

Is This a Unity Engine Bug?

No. This is expected behavior from mobile texture compression formats.

Unity applies platform-appropriate compression automatically. The artifacts appear when the compression level is too aggressive for the visual style of your game.

Final Thoughts

Color banding and artifacts on mobile are not random. They are a predictable result of compression choices.

Review platform overrides carefully. Use higher-quality formats where necessary. Reserve uncompressed textures for only the most sensitive visuals.

With the right balance, you can maintain visual quality while keeping your mobile build optimized and efficient.