User manual

Scanning tips
Before you scan paper documents, consider the following tips and techniques:
● Acrobat scanning accepts images between 10 and 3,000 ppi. However, if you select
Searchable Image or Full Text & Graphics for PDF Output Style, input resolution of 144
ppi or higher is required, and input resolution higher than 600 ppi is downsampled to 600
ppi or lower.
● For most pages, black-and-white scanning at 300 ppi produces text best suited for
conversion. At 150 ppi, OCR accuracy is slightly lower, and more font-recognition errors
occur; at 400 ppi and higher resolution, processing slows and compressed pages are
bigger. However, if a page has many unrecognized words or very small text (9 points or
smaller), try scanning at higher resolution. Scan in black and white whenever possible.
● When Recognize Text Using OCR is disabled, the full 10 to 3,000 ppi resolution range
permitted by Acrobat may be input, but the recommended resolution is still 144 and
higher ppi. For Adaptive compression, 300 ppi is recommended for grayscale or RGB
input, or 600 ppi for black-and-white input.
Note: Pages scanned in 24-bit color, 300 ppi, at 8-1/2--by-11 inches (21.59cm-by-
27.94cm) result in large images (25 MB) prior to compression. Your system may require
at least twice that amount of virtual memory available to be able to scan. At 600 ppi, both
scanning and processing typically are about four times slower than at 300 ppi.
● Avoid dithering or halftone scanner settings. These can improve the appearance of
photographs, but they make it difficult to recognize text.
● For text printed on colored paper, try increasing the brightness and contrast by about 10%.
If your scanner has color-filtering capability, consider using a filter or lamp that drops out
the background color. Or if the text is not crisp or suffers from dropout, try adjusting
scanner contrast and brightness to clarify the scan.
● If your scanner has a manual brightness control, adjust it so that characters are clean and
well formed. If characters are touching, use a higher (brighter) setting. If characters are
separated, use a lower (darker) setting.
Characters that are too thin, well-formed, and too thick