|CanoScan LiDE40 is Canon's A4 USB CIS flatbed image scanner.By Qurren (Qurren's file) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons|
A flatbed scanner has a flat glass plate, similar to a copy machine, and the same type of copy machine light source. Some of the flatbed scanners today use a charge-coupled device (CCD) or a contact image sensor (CIS) as the image sensor. The light source for flatbed scanners is usually a xenon, LED or cold cathode fluorescent type. An alternate type of scanner uses a contact image sensor (CIS) scanning consists of a moving set of red, green and blue LEDs strobed for illumination and a connected monochromatic photodiode array under a rod lens array for light collection. See Wikipedia: Image scanner.
The main issue in using a flatbed scanner is the time it takes to make one digital copy of a document or photograph. It can become extremely tedious to raise and lower the lid and replace the documents or photos to be copied. The image quality is usually very good, depending on the software supplied by the manufacturer. Most of the flatbed scanners available today, scan in color, black and white an gray scale. The newer models have all moved well beyond the needs of high quality archival standard scanning. I will be talking a lot more about scanner resolution in future posts.
You could spend a considerable amount of time comparing flatbed scanner models, or you could simply walk into the nearest store selling the devices and buy the first one that caught your eye. You would probably end up with a perfectly adequate scanner. But I suggest a mid-road approach. Spend some time reading reviews and thinking about the following considerations:
- How many documents do you expect to scan?
- How long will you spend scanning?
- Do you intend to use the scanner for purposes other than genealogy?
- Are you concerned about archive quality or do you want quick and dirty?
As you think through the physical process of scanning, you must also consider what you are going to do with the computer files created by the scanner. I will also be posting more information about understanding and using the different file formats. It does no good to purchase a scanner and then fail to learn how to transfer the files and use them as media attached to your genealogical database whether online or on your own computer.
Depending on the amount of paper you need to scan and the time you have to spend doing the scanning, you may wish to look into the possibility of purchasing a sheet-fed scanner. This is also a topic for another post. As you can probably tell, scanning documents for use in a genealogical context can be a somewhat technical area. I only have to go online and look at the quality of the images uploaded to family tree websites to know that many researchers lack a basic understanding of the way to scan an image or how to handle the digitized image file. Of course, the scanned image can be no better than the original, but sometimes there is a high quality scanned image already available of the ancestor and someone has uploaded a very, very poor quality copy of exactly the same image. There are a lot of considerations in making images for genealogical purposes besides those involved in the technology of the various scanning devices.
Here are two images of exactly the same photograph from the FamilySearch Memories section. Both images are copies from an original photograph. A high quality scan of the original is available on the same page as these two photos.
This is apparently the photo from which the two copies were made.
There are a lot more considerations about image quality and choice than just the technology involved in making scanned images.
Here is a list of the previous posts in this series: