[Caspar]

Which of the existing maps use the *.bumph files?

Almost all.

Has anyone got a sample set of normal *.tga ground textures and correponding *.bumph files?

This is one of our original Bessarabia texture. A full set, with TGA, TGB, BumpH and Tree-file:

http://depositfiles.com/files/w48imerpq

Sidenote:
There are a few textures around, that get claimed to be produced by others, but instead are basicly made by us or the Slovakia-Team. I wish, there was more care for correct credits here at AAA.

I have added custom ground textures into

root/MODS/MAPMODS/maps/_Tex/land/summer

So am I right thinking I can make a simple bump map just by changing my texture to greyscale, changing it from *.tga to *.bumph and putting it in the same folder, or does it have to go somewhere else?

Yes and no. Yes, they must be in the same folder. No, I don't think its as simple as just that. The BumpH has to be handled a bit different, i.e. if its too noisy, it produces pretty bad results. Its hard to explain, you'll see it when you test it. Generally with this file you tell the game the heights of the things painted on your initial texture. You should then paint it that way. Lower things/areas darker, higher thing/areas brighter. Don't do too much contrast between that and don't do pure white or black.

Another hint:
Textures, which are supported by bumpmaps, behave different to the ingame light than textures without bumpmaps.
If the sun stands high, they look brighter, if the sun stands low, they look darker than normal. You can say, bumpmaps make them more sensitive.
So it would be good, when you do BumpMaps for most textures, if not ALL.