I am relatively new to this so I will appreciate all responses. I went to shoot a long exposure shot with my Nikon D70s. I had it set on bulb mode and f8. Yet when I go back to see the picture. It is simply all white. Please help, thanks

I went to shoot a long exposure shot with my Nikon D70s. I had it set on bulb mode with an aperture of f/8. Yet when I go back to see the picture, it is simply all white. What did I do wrong, or what can I do to fix it?