Thank you both. Its probably unfortunate that a default spec map may not comply with the new standards, seeing how the default files are provided to the skinner as a working base and the skinner would probably assume that following that example would be OK. I do understand how it came about though. Are the new standards written down anywhere? I feel like there are probably many standards that I am unaware of and would get tripped up by.
Greebo's tutorial has been an excellent resource, but I wonder whether that is up-to-date. It talks about the bump map file, and how it is no longer used except to create the Normal map. I'm not sure I ever created a bump map file in my earlier skinning days - I think I used to just bake in my surface effects the best I could using shadow and glare layers described in Fester's old tutorial. However I have created usable Normal maps by starting with the Diffuse map, eliminating the layers that don't have anything to do with surface deformations or texture, and then applying the nVidia plugin filter. Is that OK to do? If I need to create a bump map file as an intermediate step toward the Normal file, I'll need some refresher on how to create it.
Here is another point of confusion I have, and it came up as a result of this discussion on different materials and how they are depicted in the Specular map. I'll use Greebo's Ki.43 maps, directly from his tutorial. This is a bare metal Ki.43 with fabric control surfaces and some painted stripes and a painted band around the rear fuselage:
I have two questions. First, the rivets. Rivets are all made of the same material and depicted as dark grey dots against the unpainted aluminum fuselage. In the area of the painted band however, some rivets are shown as white dots. I assume this is depicting paint chipped off the rivet head, but why then wouldn't it be the same color as the other bare rivet heads shown on the unpainted fuselage? Why would having the paint chipped off a rivet head alter its specularity to bright white? It should be the same material now as the other unpainted rivet heads. So we have two different specular values (dark grey and bright white) for the same material (rivet heads). Isn't that incorrect, given the standard?
My other question is about the control surface (elevators and rudder) hinge shadows. Why are shadows being depicted on a specular map? Again, the surface is the same material whether it is in shadow or not, so why the difference in specular values? Honestly I don't know where the shadow layers belong now, or if we are not even suppose to create them directly - maybe the graphics engine is supposed to show them based on the sun angle and the Normal map?
I think I do understand correctly that a single material, aluminum for example, may have different specular values based on surface weathering and discoloration, paint, grease or exhaust stains, etc. But a shadow seems like a wholly different kind of effect...
EDIT: I just realized that last question may contain the explanation for bright white rivet heads - the unpainted rivet heads have weathered for some time, exposed to the elements, and are no longer shiny as they were when newer. But a rivet head that had been protected by paint until it was recently chipped off would have that shiny newness exposed....