Pdf scanner download for pc

Acrobat scanning accepts images between 10 dpi and 3000 dpi. If you select Searchable Image or ClearScan for PDF Output Style, input resolution of 72 dpi or higher is required. Also, input resolution higher than 600 dpi is downsampled to 600 dpi or lower.

Lossless compressions can only be applied to monochrome images. 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 or JBIG2 (Lossless) for monochrome images. If this image is appended to a PDF document, and you save the file using the Save option, the scanned image remains uncompressed. If you save the PDF 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 small text (9 points or smaller), try scanning at a 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 the 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.