There are three main categories of PDF documents today. These three categories are arrived upon based on the way that the file originated. The manner in which the PDF document was created will usually determine whether or not the content is locked or if it can be accessed and edited. Locked content is usually locked in an image of the PDF document.
The three categories of PDF files are digitally created PDFs, scanned PDFs, and searchable PDFs. In this article, I will be exploring these three categories in more detail.
“True” or Digitally Created PDFs
There are two main ways of creating PDF documents digitally. In one method, the PDF document is created by the use of computer software such as Excel, Word, or photo viewer. It means that the content was generated digitally using a digital device such as a computer or a camera. An alternative to creating PDF documents using software, it is also possible to create PDF documents using the “print” function where the document is printed to a virtual printer. When the document emerges from the virtual printer, it usually has a PDF file format.
In each of the methods described above for creating PDF documents the characters contained in the meta-information and text usually have a corresponding character designation. These PDF allow users to search words and phrases they contain. It is also possible to edit these PDFs in the same way that you can search through a word document. You can also convert PDF to word and vice versa when they are in this format.
The images contained in digitally created PDFs can also be deleted, moved, and resized to your preferences.
“Image-only” or Scanned PDFs
A second method through which you can create a PDF document is if you use an office scanner to scan a hard copy document and then save it as a PDF file. This is a very common practice in offices where there is need for converting hard copy documents into digital formats for purposes of archiving. Archived PDF documents can be preserved without the fear of them changing in any way so that they can be used in future if need ever arises.
Besides scanning documents, it is also possible to create a PDF document from an image or photo that is captured using a camera. Photos of these kind usually have extensions such as tiff, PNG, JPEG, and JPG among others. When these images are converted into PDF files, the image is locked into a snapshot-like image. PDF files of this kind do not allow the text or images they contain to be edited in any way.
Searchable PDF files are usually created by applying OCR on scanned PDFs or other documents that are based on images. OCR is a technology and the initials stand for Optical Character Recognition. During the application of OCR, an analysis is done on the characters and the document structure, resulting in the addition of a text layer underneath the PDF image. Once the PDF document is created, it cannot be distinguished from the original copy and it is completely searchable.