I Scanned A Mirror
'The light from a scanner hits images at a 45 degree angle -- which is why you see the scratches, and not white light.
Think about it: scan a glossy book. If the light was shining directly up, it wouldn't be able to scan anything. the light from the shiny glossy surface would reflect back into the detector.
Also: there's a piece of glass in front of the scanning mechanism itself. If the light were projected directly upwards and directly back into the detector, the reflection would ruin the image.
The detector and the light source are not in line with each other. it is no surprise that a scan of a mirror yields dark results. You're seeing a reflection of the inside of the scanner, which is quite dark (as expected).'
- Comment by Ophello