zWhen the [High Compression for Color PDF] button is pressed, characters and their backgrounds on a document are detected separately, and only the backgrounds are compressed. For a text based document, the resulting file size can be smaller while the characters remain clear.

However, note the following:

z Photographs or pictures are recognized as background and compressed at a high rate, causing degradation in the scanned image.

z Thus, this mode is not appropriate for scanning photographs or other graphical materials.

z The contrast of the image may become higher.

zIf [High Compression for Color PDF] is selected, according to the type of document, the file size may be larger than if a standard compression rate is used.

z Documents with many photographs or figures and only a few characters z Complex layout documents with multiple columns

z Documents which have a background pattern behind characters

zFor documents with many characters scanned at 300 dpi resolution, a smaller file size than that of High Compression for Color PDF is possible.

381