- Normal- This is searchable text. (like a book) However, you cannot edit any text in it. Images and text are 'one page'. The most common pdf. A PDF searchable "book" for example.
- Image Only- this is as if we just scanned the pages and combined them into a file. These are not searchable, there are only "pictures" of the exact pages.
- Image+Hidden text- This is the easiest to work with. If you have a technical manual which has drawings in it, and you want to be able to search the text, but you need the drawing to be viewable too, this is the one flavor you want. The person viewing will SEE the image, and the original text scan, but will search only the converted text which is not viewable. (it will get them to the page they are looking for.) The best way to compare it is to do a search in a text document. You'll notice a black highlight box around the word. That's what appears in a pdf file too, except that the "scanned image" is in front or viewable. If you had a page where the top half is text and the bottom is a drawing, this is where you want to have the text searchable but the drawing viewable.
- The fourth style is an adobe proprietary file format which is an intermediate pdf file in that you can edit the hidden text. Some people want to have 100% accuracy, in which case you need the 'raw file' to see the hidden text to edit before it is changed to hidden text in the pdf format. You will need special Adobe software (about $500.00 per seat) to view and edit these files, or we can, for an hourly fee.
This is always an issue. Searchable PDF is really OCR in the background of an image. The accuracy depends on the "common" words and language used. Legal documents, engineering documents have lower accuracy readings than a novel or magazine article. Abbreviations and alpha-numeric "words" are hard to convert. Depending on the type of vocabulary used in the documents, the accuracy will be highest, higher, average and of course, fair. If its poor, you're better off with just images. Also, the quality of the original document is a key factor too!