Metalness vs specular workflow is the first real fork after you learn PBR. Both models can look photoreal. They store the same physics in different channels. Plug a specular pack into a metalness shader—or the reverse—and wood turns into cheap chrome. This guide shows what each map means and how to stay consistent.

What both workflows are trying to describe

Every opaque PBR surface has a base color, a roughness (or gloss) that blurs reflections, and a rule for how much light reflects as a mirror versus how much scatters as diffuse. Metals have almost no diffuse; their color is the tint of the reflection. Dielectrics such as wood, concrete, and fabric have a colored diffuse lobe and a weak, usually greyscale, specular. Fresnel boosts reflection at grazing angles. The two workflows encode that split differently. See the complete PBR texture guide for the full map set.

How the metalness workflow stores color

Metalness uses one greyscale map. Black (0) means dielectric. White (1) means metal. Albedo then changes meaning:

  • On dielectrics, albedo is the diffuse color. Specular intensity is a fixed low value inside the shader.
  • On metals, albedo is the reflection tint (gold, copper, steel). Diffuse is forced toward black.

That compact layout is why Blender, Unreal, and Unity standardized on it. Locker3d metal textures follow it. Keep metalness binary except where rust, dust, or paint covers metal. Those covers are dielectrics on top, not “half metal.”

How the specular workflow stores reflections

Specular-glossiness, still common in some V-Ray graphs, gives you a colored specular map and a glossiness map. Diffuse stays the non-metal color. Specular color holds intensity and tint. Metals get a dark diffuse and a rich specular color. Dielectrics get a light diffuse and a dim grey specular, often around 4% reflectance. Glossiness is typically the inverse of roughness.

The extra control helps oily metal and layered coatings. The cost is more ways to break energy conservation if specular is too bright while diffuse stays full.

When to stay on metalness

Stay on metalness for almost all new work. You can download CC0 PBR textures from Locker3d and connect Base Color, Roughness, Metallic, and Normal with no conversion. Interiors built from wood, floor, and concrete are dielectrics: metalness stays at 0. Only raw metal uses 1. Maintaining a second naming scheme for one hero asset is rarely worth it.

When specular still makes sense

Use specular when the renderer or studio template requires it. Some offline graphs still expose specular color and glossiness as the native pair. Convert once at import and keep working files in the studio format. Do not maintain two master packs “just in case.”

Converting packs without wrecking values

  • Dielectric pixels: copy albedo to diffuse; set specular to a dark grey; gloss = 1 − roughness.
  • Metal pixels: set diffuse near black; copy albedo into specular color; same gloss conversion.

Specular to metalness is lossy. You infer metalness from a bright colored specular plus a dark diffuse. After conversion, albedo stays sRGB; roughness, gloss, metalness, and normal stay non-color. Wiring is in how to apply PBR textures in Blender. Locker3d files are CC0, so you can convert and ship them. More notes: PBR textures for beginners and the blog.

Frequently asked questions

Which PBR workflow should I use in Blender, Unreal, or Unity?

Use metalness-roughness. Principled BSDF, Unreal’s default lit material, and Unity URP/HDRP all expect it. Most Locker3d CC0 packs ship metalness maps for that reason.

Can I convert a metalness pack to specular-glossiness?

Yes, as an approximation. Dielectrics get a dim greyscale specular; metals move albedo into specular color and darken diffuse. Gloss is usually 1 minus roughness. Tweak rust and dusty metal by hand.

Why do mid-grey metalness values look wrong?

Real surfaces are almost fully metal or fully dielectric. Mid-greys invent a hybrid that does not exist, so you get plastic chrome or dull foil. Use 0 or 1; put dirt and rust in albedo and roughness.