Portable [Preservation Quality] Document Scanner
A professor of ethnomusicology asked me for advice on choosing a document scanner for his trip to Paraguay. He said he will need to scan many music scores on tabloid size pages (22inches by 17inches when laid out open). A large, 35lb flatbed scanner is impractical and consumer document scanners (such as the one made by Fujitsu) do not scan documents that size at a quality high enough for preservation.
The Riley Digitization Center at Baylor uses two DSLRs (Canon 5D Mkii) in one of their scanners that they use for digital preservation. So, with this already accepted precedence, I decided to experiment with using DSLRs to scan documents. After a bit of experimentation, I came up with something that works quite well. I chose to utilize two flashes off camera to avoid reflection from shiny documents. The wireless remote serves both the practical purpose of making it easier to turn pages quickly and the technical purpose of ensuring that the camera does not move once it has been perfectly calibrated.
I’ll go ahead and note the settings (also included in the instructions below): 1/16 flash power; 1/125 shutter speed, 7.1 f-stop, 100 ISO.
$500 (after $100 rebate) = (1) Canon SL1
$150 (after $50 rebate) = (1) Canon 40mm lens
$20 = (1) Canon 40mm lens hood
$280 = (2) Cactus RF60 Flash
$60 = (1) Cactus Wireless Flash Transceiver V6
$30 = (2) Vello Light Bouncer Kit
$20 = (1) Canon RC-6 wireless remote
$200 = (1) Manfrotto tripod legs
$70 = (1) Manfrotto tripod head
$120 = (6) 16GB Sandisk SD memory cards (water, shock, and x-ray proof)
$30 = (1) Wasabi battery kit
$50 = (1) Lowepro CompuDaypack Photo 250
Total = $1610
Step 1 - Prep. Format the SD card using the camera (go to menu) before taking the first photo with that card. Make sure all your batteries are well charged.
Step 2 - Setup the tripod and flashes. Make sure the camera is positioned perfectly level over the middle of the document. Unfortunately, the flashes need to be about 14inches off the floor for optimal exposure.
Step 3 - Set the flash transceiver to transmitter (“TX”).
Step 4 - Set the flash modes to slave (“S”) and set the flash zooms to 24mm.
Step 5 - Set the camera to program (“P”).
Step 6 - Set the lens to auto focus (“AF”).
Step 7 - Calibrate the position of the camera: press the live view button on the camera, partially press down the shutter button to focus, and carefully adjust the camera so that the document is framed perfectly (leaving a little bit of room to crop off in post). Once the camera is perfectly positioned and in focus, switch the lens from auto focus (“AF”) to manual focus (“MF”) while still partially pressing the shutter button (that will ensure it is in perfect focus and that it will not have to be refocused every time you take a photo).
Step 8 - Switch camera to manual (“M”).
Step 9 - Adjust the camera to the following settings:
Step 10 - Take photos using the wireless remote (note, you have to point the remove at the front of the camera because it uses infrared technology).