I tried this but my white sheets always end up looking blue and all the wrinkles tend to show. Yours look very professional.
I sometimes have "blue" and it's usually a combo of outside light quality, and needing a warmer setting on the camera. Unfortunately some small digitals don't give you enough options on settings. Mine is a Canon G10 with a nice large sensor inside of it, and its pretty detailed for being a smaller point and shoot style. My husband is a professional photographer...I am NOT...but his knowledge may occasionally "leach" into my brain and that helps too.