I am trying to take a photo of a banner against an off white wall. Is there a way to get a pure white background and the banner colors not be overexposed? I am using a point a point and shoot camera on auto settings. Right now, the picture looks a little/blueish.
With the banner against the wall, rather than separated from it, you have to make the subject look right and fix the background in PS. Use a tripod and take a series of bracketed exposures. Tools for HDR/tone mapping might make quick work of the resulting stack, or IAC the overexposed version is good for making the mask.
I have a similar issue with scanning old magazine pages: I use color-match selection and delete the off-white paper leaving only the ink. Making the wall evenly lit would be the most helpful there.