Layer mask problem photoshop?

Question: Layer mask problem photoshop!?

I use photoshop (7) quite frequently, but lately for some odd reason every time I use layer mask only black and white colors are available!. When I go back to the standard pic my colors are available!. And to make matters worse I can't inverse while I'm at layer mask!. Any help please!?Www@QuestionHome@Com

Best Answer - Chosen by Asker:

if you're working with a layer mask, the only colors you need are black and white!. black reveals and white conceals the layer below itWww@QuestionHome@Com