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. Scan in black and white whenever possible.
If a page has many unrecognized words or small text (9 points or smaller), try scanning at a higher resolution. 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 you save the PDF using Save As, the scanned image may be compressed.įor most pages, black-and-white scanning at 300 dpi produces text best suited for conversion. If this image is appended to a PDF document, and you save the file using the Save option, the scanned image remains uncompressed. 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.
Also, input resolution higher than 600 dpi is downsampled to 600 dpi or lower. If you select Searchable Image or ClearScan for PDF Output Style, input resolution of 72 dpi or higher is required. Acrobat scanning accepts images between 10 dpi and 3000 dpi.
