Operation Manual

Table Of Contents

USING ACROBAT X STANDARD

Creating PDFs

Last updated 10/11/2011

• To apply lossless compression to a scanned image, select one of these options under the Optimization Options in

the Optimize Scanned PDF dialog box: CCITT Group 4 for monochrome images, or Lossless for color or grayscale

images. If this image is appended to a PDF document, and the file is saved by Save, the scanned image remains

uncompressed. If the PDF document is saved using Save As, the scanned image may be compressed.

• For most pages, black-and-white scanning at 300 dpi produces text best suited for conversion. At 150 dpi, OCR

accuracy is slightly lower, and more font-recognition errors occur; at 400 dpi and higher resolution, processing

slows and compressed pages are bigger. 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, full 10-to-3000 dpi resolution range may be used, but the

recommended resolution is 72 and higher dpi. For Adaptive compression, 300 dpi is recommended for grayscale

or RGB input, or 600 dpi for black-and-white input.

• Pages scanned in 24-bit color, 300 dpi, at 8-1/2–by-11 in. (21.59-by-27.94 cm) result in large images (25 MB) before

compression. Your system may require 50 MB of virtual memory or more to scan the image. At 600 dpi, both

scanning and processing typically are about four times slower than at 300 dpi.

• Avoid dithering or halftone scanner settings. These settings 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 isn’t

crisp or drops out, 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.

Recognize text in scanned documents

You can use Acrobat to recognize text in previously scanned documents that have already been converted to PDF.

Optical character recognition (OCR) software enables you to search, correct, and copy the text in a scanned PDF. To

apply OCR to a PDF, the original scanner resolution must have been set at 72 dpi or higher.

For more information on text recognition, see these videos:

• Recognizing Text in Scanned PDF Documents: www.adobe.com/go/lrvid_025_acrx_en

• How to Edit a Scanned PDF: www.adobe.com/go/learn_acr_edit_scans_en

Note: Scanning at 300 dpi produces the best text for conversion. At 150 dpi, OCR accuracy is slightly lower.