I recently have used my 35mm camera that i have not used lately. put in new batteries and it works fine?

but i bought 400 speed film and i told my wife why not just use 200 because it was going to be used outdoors. well the pictures are fine, but it has a pinkish haze where it should be white. is it the film might be old? or is that because of 400 speed film? cant understand, maybe it was the film itself, so what u think it could be.