PDF Version - Select a PDF format from the drop-down list.
PDF/A-1b (ISO 19005-1) compliance - Check this option to indicate that ScanToPDF should create a PDF file that is compliant with the PDF/A-1b standard
PDF/A is a file format for the long-term archiving of electronic documents. It is based on the PDF Reference Version 1.4 from Adobe Systems Inc. (implemented in Adobe Acrobat 5 and latest versions) and is defined by ISO 19005-1:2005, an ISO Standard that was published on October 1, 2005.
Color image quality - Use the selector to set the required compression (High Quality / Low compression, larger file size and vice-versa)
Lossless Compression
Set the slider to the lowest compression. This will make the compression true lossless (as shown below)