Make sure that you have set the Original Type setting to "text" or
try setting the Background Suppression setting to "Off" for originals on dark or colored paper. If you need help verifying these two settings, the WC 5765 Knowledge Base will show you how, step-by-step. Just type in "Light Faint Faded" without the quotes, into the search field and click on the first search result.
When I scan documents with notes written in blue ink, the scanner isn't picking up the notes unless I darken the document significantly, which can alter the appearance of the rest of the document. Also have to change it each time, which can be time consuming. Is there a separate setting I can alter that will be permanent and allow the scanner to read blue and black without darkening?