Applying textures to loops and corkscrews.

Hi, my name is Bobby and here is a little something Iv’e been learning, this is a loop de loop that I created using the screw tool, I only used a flattened out cube to create it, I can somehow paint it one solid color but applying custom textures that I create with gimp, my object turns all black on top or white, here is a picture of what I’m learning.

so here is a screenshot of it.