Fix: Unity 2D Light Not Affecting Sprites in URP

Here is how to fix Unity 2D Lights that do not illuminate your sprites in URP. You add a Light 2D component, crank its intensity to 5, and the sprite stays at exactly the same brightness it had before. The Light 2D is real, the URP package is installed, but nothing connects. Three settings need to align: the renderer type, the sprite material, and the target sorting layers.

The Symptom

Sprites in your scene render at full brightness regardless of nearby Light 2D components. Toggling the lights off makes no visible difference. Light 2D gizmos appear in the Scene view but the rendered Game view ignores them. Sometimes the entire scene is full-bright; sometimes pitch black with no lights helping.

What Causes This

Sprite uses Sprite-Default material. The default sprite material is unlit. It outputs the sprite texture color directly without sampling any light contribution. 2D Lights have no effect on it.

URP asset uses Forward Renderer instead of 2D Renderer. The Forward Renderer ignores Light 2D components entirely; they only work with the 2D Renderer Data type.

Sorting layer mismatch. Each Light 2D has a Target Sorting Layers list. Sprites on layers not in the list are unaffected. The default list often includes only the Default layer.

No global light. The 2D Renderer does not use the Lighting window’s ambient color. With no global Light 2D, sprites fall back to whatever fallback the renderer provides, which can be black or unlit white depending on configuration.

The Fix

Step 1: Switch to the 2D Renderer. Open your URP Asset (Project Settings → Graphics → Scriptable Render Pipeline Settings). In the inspector, drag a 2D Renderer Data asset into the Renderer List. If you do not have one, create it via Create → Rendering → URP Universal Renderer (2D).

Step 2: Change sprite materials to Sprite-Lit-Default. Select all SpriteRenderers (filter the Hierarchy by component, or multi-select) and set Material to Sprite-Lit-Default.

// Bulk-update at runtime if needed
using UnityEngine;

public class PromoteSpritesToLit : MonoBehaviour
{
    [SerializeField] private Material litMaterial;

    [ContextMenu("Promote Sprites")]
    void Promote()
    {
        foreach (var sr in FindObjectsByType<SpriteRenderer>(FindObjectsSortMode.None))
            sr.sharedMaterial = litMaterial;
    }
}

Step 3: Add a Global Light 2D. Right-click in the Hierarchy: Light → 2D → Global Light 2D. Set Intensity to 1.0 and Color to white. This provides ambient illumination that makes sprites visible even without nearby point lights.

Step 4: Configure target sorting layers. On each Light 2D, expand the Target Sorting Layers list and add the layers your sprites are on (for example, Background, Default, Foreground). Lights only illuminate sprites on listed layers.

Step 5: Verify with a strong test light. Add a Spot Light 2D with intensity 5 right next to a sprite. If the sprite gets brighter, the pipeline is working — you can then dial intensity down to a normal value. If still no change, the material is still not Lit.

Shader Graph Materials

Custom 2D shaders need to be based on the Sprite Lit master node. If you started from Sprite Unlit, the shader will never sample 2D Lights regardless of how the Light 2D components are configured. Open the shader graph, change the master node, and rebuild.

Normal Maps For 2D Lights

Once Lit materials are in place, Light 2D direction can drive shading via the sprite’s secondary normal map texture. In the SpriteRenderer’s Sprite Editor → Secondary Textures, add a normal map under the name _NormalMap. The result is per-pixel directional shading from 2D Lights.

“2D Renderer, Lit material, sorting layers, global light. Four checks and the sprites finally listen.”

Related Issues

For other URP rendering issues, see URP Shader Not Rendering in Build. For sorting layer problems, see Sprite Renderer Not Visible.

Sprite-Lit-Default. 2D Renderer Data. One Global Light. Layers in the list. Done.