bump map problem

im having problems with adding a bump map. I am using the NOR modifier for the image. this is what you use for a bump map, right? I was taught that in bump maps, the white area is brought out, while the black is brought in, but when I render, the opposite happens :frowning:

if someone can help its greatly appreciated.

When you make a normal map texture you press the β€˜nor’ button in the MapTo Panel. The text of the button turns white. Pressing this button again inverses the normal map, the text of the button turns yellow.

http://mediawiki.blender.org/index.php/Manual/PartIV/Map_To