A resolution of 300 to 400 dpi is required to obtain optimal results in Readiris. When you try to scan or open images of a resolution lower than 200 dpi or higher than 600 dpi, Readiris will display a warning.
When you are faced with these kind of images, the best thing you can do is re-can the images in an appropriate resolution. If that's not possible, there are few tips and tricks that help you obtain better results:
Tip 1
When scanning images of an unknown resolution or images of which the file header displays an incorrect resolution, make sure to select the option Process as 300 dpi:
On the Readiris menu, click Preferences.
Click the Preprocessing tab.
Select the option Process as 300 dpi.
When this option is selected, Readiris treats the images as if they had a 300 dpi resolution.
Tip 2 (Readiris Corporate only)
Make sure that favor OCR accuracy over speed when processing low-quality documents:
On the Readiris menu, click Preferences.
Click the Page Analysis tab.
Make sure the option Favor accuracy over speed is selected.
Note: When you are processing low-resolution faxes, there is no need to take special measures. Readiris detects the typical fax resolutions 100 x 200 dpi (normal quality), 200 x 200 dpi (fine quality) and 200 x 400 dpi (superfine quality) and preprocesses these images automatically to ensure optimal results.