Taking as a reference a real material, a corroded metal in this case, we will see how to create the complete material in Blender thanks to the following techniques:

realization of the base surface in a procedural way, therefore without the use of external textures but using only the Blender nodes;
texture painting to draw the rust created on the metal and to draw the incisions on the surface;
use of brushes made in Photoshop;
addition of a procedural bump map to simulate surface roughness and micro imperfections;
creation of a roughness mask to vary the distribution of the specularity.

With this course you will learn the basic techniques to fully realize a realistic material.  

Lang: Italian