For most office applications you will get the smallest file sizes (+ a perfectly
good quality scan) if you scan in B&W. Greyscale and colour generate files which
can be much larger than B&W. If scanning to greyscale or colour (& there can be
good reasons to do so), stick to 256 shades of grey and true (24-bit colour) – Other
variants can sometimes be restrictive with other viewing tools.
General A4 B&W documents (such as invoices, letters etc.), do not need to use a high
scanning resolution. Current document scanners scan up to 600 or 1200dpi, but this
is not necessary for day to day scanning. We usually recommend 200-300 dpi max.
In an attempt to keep file sizes to a minimum (& if suitable for your application),
colour documents are frequently only scanned at 100 or 150 dpi (only photos routinely
need higher resolutions). For B&W or colour, the higher the resolution the more
space the resultant file will take up on your PC (the scanner also runs more slowly).
If you have an A3 scanner, you can turn A4 documents by 90 degrees & scan them in
landscape instead. This will speed up the scanner throughput considerably as the
scanner has a shorter length of paper to feed for each page. Most modern scanner
drivers have either an option to auto-rotate the output or to auto-sense the orientation
of the page (based on text content).
Automatic Document Feeders (ADF)
All the scanners described on this site have an ADF. The capacity of the ADF is
usually between 50 and 100 sheets. Do not be tempted to overload the hopper – The
time taken to fix a paper jam or misfeed frequently exceeds the potential time saving
of filling the paper stack to overflowing.
Within the business environment there are two main file formats that you should consider.
The TIFF format is a widely recognised standard (early versions still drive “old-fashioned”
fax machines) and is easily readable by most image viewing tools. The alternative
is to use the PDF format (Adobe Acrobat) – This is in essence also a TIFF file but
with an Adobe “wrapper” around it (this is how it can add text searchable, encryption,
bookmarks, etc). Most people are extremely familiar with the free Acrobat Reader
(nb. The Acrobat creator tool usually costs extra). Contact us to discuss the various
merits of each format.
Optical Character Recognition
Many scanners are supplied with bundled software that include the facility to generate
text-searchable images (usually Adobe Acrobat PDF format). If you do not need it
switch it OFF. It reduces the need to scan to higher resolutions (typically 300
dpi in the minimum for successful OCR) and, most importantly, it typically slows
the scanning process down massively – There is no point having a 40ppm scanner, if
it is going to OCR images at a rate of <5ppm.