Here’s a question which came in to my email just now:
“Could I process a RAW file in Photoshop to achieve a similar effect as if I had used a Polaroid lens filter?
Or would I be better just using the Polaroid filter?”
The answer is that you can never imitate the effect of polarizing light (which changes the way reflective surfaces look, and deepens or lightens the sky blue according to the zone of the sky relative to the sun’s position. But you can use Adobe Camera Raw (CS3 versions) to deepen skies you never thought could be rescued.