Quick scan hints

I know, you just want to get started

• If scanning to contribute images to this site: Scan and save at 300 dpi. This preserves adequate details for most certificates. Scan at a resolution that allows you to read printers' names.
• If scanning for your private purposes: Scan at any resolution you want with the understanding that the higher the resolution the slower the response of any programs that use those images.
• If scanning in order to post sales on eBay: 200 dpi will probably be adequate for all but the smallest documents such as transfers and receipts. 
• Save as "medium high quality" JPGs (JPEGs). JPGs images are smaller than other formats and are perfectly fine for certificates unless you modify and save images several times. JPGs allow users to control image "quality" which is really a code word for how much information to save. The JPG format is considered a "lossy" format in that it purposely discards repetitive information during the save process. Image deterioration is probably acceptable when you scan at resolutions close to your final needs. I suggest saving  certificate images at about 75% to 80% "quality." 
• TIF, GIF and PNG formats are "lossless." Use them if you need to open, modify and save images several times or if file size is no concern.
• Save scans as JPG, GIF or PNG formats if you want to display on the web. PNGs are about seven times larger than JPGs, so are slow to load if displaying large images on the web.
• Scan against WHITE backgrounds if you can't see black text showing through from the back.
• Scan against LIGHT GRAY posterboard if certificates are thin enough to see text printed on the back. After scanning, you may need to lighten images to make them look better.
• Scan against LIGHT GRAY posterboard if images turn out yellow.
• Scan toward the middle of the glass and keep your certificates away from the frame. You can get certificates stuck under the frame and lose a corner tip during extraction. Straighten and crop later.
• Do not assume the edges of certificates are parallel to their borders.
• Do not worry about getting your certificates perfectly square on your scanner. Those problems are easy to correct with image manipulation software. (See Straighten images.)
• Make several overlapping scans if your certificate is too large for your scanner. Most certificates are too large for most entry-level scanners anyway. Scan in several pieces with at least an inch and a half or more overlap . When scanning in pieces, always keep the top of your certificate facing the same direction. (See Scanning Large Certificates for more information.)
• Avoid reducing images during scanning. (Why?)
• IF your scanner software allows,
  • turn off automatic color adjustment
  • turn off automatic exposure
  • turn off automatic sharpening
• Scanning software that comes with scanners usually lacks many features that your scanner actually will handle. Consider third party scanning software such as VueScan or SilverFast.