DIY High-Speed Book Scanner from Trash and Cheap Cameras

Step 35 Lighting: The Solution, I Said It Already

So perhaps surprisingly, the most sensible choice was halogen lighting.

On my first scanner, I bought new halogens and found that their lack of flicker, super-high output and reasonable price was perfect for this application. The bumpy hexagonal lens system they put on outdoor bulbs diffuses the light very nicely. And then, just in time for building the second scanner, I found a source of recycled halogen bulbs -- the Habitat for Humanity ReStore. At our ReStore, they have salvaged bulbs for 1.50 each, a tenth of the new price. FINALLY, the white balance of your camera can (and should) be set to Tungsten, which perfectly corrects for the warm color cast of these lights. In other words, your cameras come preset to use these things. It saves you time and effort and a whole step of color-correcting later.

Comments

[AutumnJazz]

Most, if not all cameras made in the past few years, allow you to set a custom white balance. Just point them at a white surface (or borrow an Expodisc), hit whatever the camera calls its custom white balance function, and there you go. Perfect color.

[europanorama]

The russians have constructed a HIGSHSPEED-BOOKSCANNER. maybe someone with time can find more on the net.

[daniel_reetz]

You don't need to use custom white balance if you use the bulbs I suggested and the white balance I suggested. It's simple and consistent to do it this way.

[AutumnJazz]

With the software, which seems to white balance anyway, I don't think camera WB matters much.

[daniel_reetz]

It does make a pretty big difference, because if you set it incorrectly you can have bad (clipping) data in one or more color channels.