… for Visual Effects
Tip #469: What is a Bump Map?
Bump maps provide texture to objects based on grayscale textures.
Typically, bump maps are used to apply texture to a smooth object.
Bump maps are 8-bit grayscale images. This means that they only have 256 values between black and white. These gray-scale values are used to tell the effects software how to texture an object.
In this screen shot, a texture (right) is applied to a smooth image (center) using a bump map effect to give the final image (left) texture.
In this example, to create the source texture for a bump map, a high-amount of visual noise was applied to a mid-tone gray background using Photoshop.
Bump maps are highly useful in creating texture, but they don’t change the actual shape of an image. This means that if you are creating cast shadows, the shadow will mirror the source object, not the bump-mapped finished effect.