Using different maps to create a more realistic look

Materials in Unreal Engine 4 are made of several different textures working together to provide a realistic result. Generally, a material for a game asset has at least two to three different texture maps that are being manipulated by different mathematical nodes. These maps are usually a Diffuse map, a Specular map, and a Normal map:

The coloring of the Artifact is determined by the Diffuse map

Diffuse maps are the basic colors that we have painted on our objects. Unreal accepts these textures in the Material Editor as the object's Base Color. These maps generally contain color and pattern information that is painted directly onto a copy of the object's UVs in programs such as Photoshop. Simply put, this type of map contains the surface colors of our object.

Next is the Specular map:

The Specular map controls how light behaves when it hits a surface

Specular maps control how shiny or dull a surface appears to be and can be hand painted or...