Search function difficulty with particular pdf documents

[owensb]

I recently downloaded the free version of PDF Xchange viewer because of its search functionality. I have found that the search function works with some of my pdf files but not with others.

Is this an issue related to settings in the program itself or with the particular pdf document? Many are pdfs of articles that I receive from a variety of sources from interlibrary exchange.

[owensb]

Additional data suggest this is a document related issue. When I am able to search the document in Xchange, I can search it in Adobe. When I am not able to search the document in Xchange, I cannot search it in Adobe.

So, my question is, how can I make a non-searchable document searchable?

[Bhikkhu Pesala]

Some PDF files contain no text — they are just scanned images. There is nothing you can do to make such documents searchable, other than using OCR software to convert them to readable text.

[Stefan - PDF-XChange]

Hello Owen,

As in the discussion we are having with e-mails, this is due to some of the files being images only, while others might be text based, or contain an invisible layer of ORCed text above the image which text while invisible is still available for our search engine.

Best,
Stefan