I used a polarising filter for this photo. Unfortunately, I didn't notice until I was back at the computer that the sky was almost black. (It was so bright when I took the photo that I couldn't see the camera's LCD very well.) I'd like to recover the blue sky in Lightroom; can anyone suggest how? Increasing luminance doesn't work; I think there just isn't enough blue there.
1/500s at f/9, ISO 100, EF-S 17-85mm, focal length 59mm.