The research continues, this time with low light values.
Once I saw that the dirt lines I added to the specular map were shinier, it hit me: Blender considers white surfaces grainy and black clean, so they are more reflective. That means it was inverted all along!
Once I inverted that, the correct specular differences appeared.
Increasing the reflection values to get a more metallic feel.
Working on the diffuse maps to add more dirt.
Adding dirt and scratches.
Added dirt to the flaps.
Closeup that shows a very bad panel line on the nose.
Increasing reflectivity once again on the specular maps.
This was my goal: Reflective but only on a close distance.
I kept adding labels and warning signs, and since the motors are thermonuclear, a Radioactive warning and a label for the International Nuclear Society.
Getting to a very nice point! Adding more smoky marks and weathering.
The right amount of dirt to make it look realistic.