Specular Map
A texture that controls the intensity and color of specular (mirror-like) reflections across a 3D model's surface on a per-pixel basis, enabling varied shininess within a single material.
A specular map defines specular reflection characteristics of a 3D surface as a texture. Brighter areas produce stronger highlights while darker areas appear matte, enabling varied glossiness within a single material.
- Grayscale mode: Single channel from 0 (no reflection) to 255 (maximum). Creates variation like scuffed leather showing more shine or dirt reducing metal reflections
- Color mode: RGB specifies reflected light color. Metals exhibit colored reflections (gold reflects yellow, copper reddish), requiring color specular maps
- Specular/Glossiness workflow: Traditional PBR combining specular (reflection color) and glossiness (smoothness) maps. Used by Unity's Standard shader
- Metallic/Roughness relationship: The modern workflow (Unreal Engine, glTF) separates specular's role into metallic maps (metal/non-metal) and roughness maps (microsurface detail)
In Substance Painter, the Specular Level channel adjusts non-metal reflectance (baseline 0.04 = 4% for dielectrics). Games sometimes pack specular data into the albedo alpha channel to save VRAM. Understanding both workflows is essential for cross-engine asset portability.