I have an HP 4890 scanner, supposed to be top-of-the-line flatbed
scanner. It scans up to 16 slides at a time. Some of the slides in my
collection are indoor shots where the lighting was too dark. When I
scan a batch, it does the "pre-scan" and finds all the pics putting
dashed lines around each. Well, it does not find the dark/underexposed
pics, so can't scan them. But there must be some adjustment to allow
you to scan a dark slide, surely! Some light/dark threshold
adjustment? How do you do this?