Scanner Inversion

[Ira Solomon]

I wanted an image of an area on the bottom of a pipe (smoking, not
plumbing) to show on Ebay. The area contains the maker's name,
location, etc. I decided to scan it, rather than photograph it,
because I could get the area flat on the scanner platen, but would
have had a very hard time holding it flat for a photo.

I got a wonderful image (Epson 4990), but the scanner did something I
don't understand. It made the words carved into the wood seem as if
the were above the wood. At the edge of the area the are carvings in
the wood that show up in the scan as if they protruded from the wood.

My knowledge of optics is clearly not what it should be and I would
appreciate an explanation. I would be happy to send the image to
anyone who wants to see it.

Thank you.

Ira Solomon

 

[Bart van der Wolf]

SNIP

I got a wonderful image (Epson 4990), but the scanner did
something I don't understand. It made the words carved into
the wood seem as if the were above the wood. At the edge
of the area the are carvings in the wood that show up in the
scan as if they protruded from the wood.

My knowledge of optics is clearly not what it should be and
I would appreciate an explanation. I would be happy to send
the image to anyone who wants to see it.

This is probably due to the direction of the light. Humans 'vision'
assume light to come from above, thus casting shadows below. If this
happens to be the case with your scan, you simply rotate the pipe 180
degrees before scanning, and our vision will no longer play tricks on
us.

Bart