How can I create a Bump Map?

I have bought the book on iRender and understand the concept of reversal for a bump map on a stone wall, but how do I actualy do it?

Creating your own "true" bump maps of complex images is probably difficult. You would take a standard image of the surface and color it by depth. A good Photo Shop user may be able to do this.

But you may be able to add realism to some images more easily.

Here you could use a paint program to define bump levels - even just black and white.

Here is a brick wall image:

Here I have used a paint program to put the bricks at one level, and the mortar at another level:

Here is a rendering of the base texture on a brick wall with no bump maps:

Here is a rendering with this bump map applied to the rendering as well.

But we also have another feature, called "auto Bump" which provides a similar effect to this simple bump map.