I am looking to scan old slides before they deteriorate too. I have scanned hundreds of color slides (I photograph them directly with a special lens) and I was very surprised when I wanted to move into positive. I have not found this function in Photoshop or Picasa or another. The function exists for black & white but not color. I am looking for a way to spend my color negative images into positive. Is it possible for Lightroom to convert negatives to positives?