Originally posted by jgredline Here is an interesting to me situation.
I was scanning some film a few minutes ago, when I noticed I scanned a picture backwards. I flipped the film and scanned it the right way, but am now getting to different looking pictures...
If I had to guess, I'd say auto levels/exposure in the scan software is picking different white and black points because of the different crops. I haven't used Vuescan in a while, but I believe there is an option to do the initial crop tighter, but scan with a bigger margin to get the whole image. If it doesn't, manually crop tighter and see what you get. Any stray light coming in around the image will become the new white/black point and can also cause flare.
Edit: A lot of scanners request the emulsion side down and automatically flip the image in software. If you prefer it that way, there's nothing wrong with doing it that way. I also believe Vuescan has a "tickbox" to mirror the image for you.