I need to scan a wooden object that has a very shiny finish on it with our laser scanner. What can I spray or put on it to dull the finish, and remove later, without damaging the existing finish? I think the finish is a polyurethane, so it would be wipeable with water or a mild solvent.

Use a dulling spray:

http://www.krylon.com/main/product_template.cfm?levelid=5&sub_levelid=8&productid=1822&content=product_details

You can also use a food safe spray release agent. Don't overdo it with the spray...a little bit goes a long way.

-B

Just come across a suggestion I'll pass on.
"Cheap hair spray, then dust with flour. ....It washes off"

Test first.
John

you can use a material called: Spotcheck SKD-52 as well. I have had great success using this to reduce the reflectivity of the object i am scanning.

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Although I haven't tried it personally, a suggestion I was given was a spray foot powder like Desenex. Basically, spray-on white powder. I plan on trying it on the next project I have lined up.

You can try straight talc too.