Photoshop CS2 v.9 Help - Layer Masks

I'm making a blend for my writing journal which is mostly fanfiction. Anyway, I use layers masks to erase parts of the photos I don't want. Suddenly when I delete a part of the image, the part I deleted is still there but as if I didn't have the opacity on the eraser brush set at 100%. I do have it set there I even checked to make sure my colors were white and black. Anyone knows what's up? Its rather annoying and it doesn't erase fully when I go over it a second time.



Nevermind, I figured it out on my own. The black was really a very dark blue. :) So yes, if this ever happens to anyone, double check your colors. :)