Double PDF: what does it mean?

In a double PDF, the first layer is an image, and the second layer is text, and the image and text are aligned. The text of the image can be copied and pasted into other text editing software (like Word).

A dual-layer PDF, derived from a standard PDF file, has the following characteristics: it contains both text and image layers, combine pdfs for free windows,with corresponding positions. This type of PDF can be created by quickly scanning data and generating a searchable document. The top layer is the original image while the bottom layer is the recognized results, allowing for 100% retention of the original layout and supporting functions such as selection, copying, and retrieval. This type of PDF is beneficial for creating an indexed database and facilitating scientific management.

There are two types of two-layer PDF files. One is an image file, which can be cleaned up using OCR software, corrections, and recognition; the second is a text-based file. Converting a WORD file into a two-layer PDF file is the most common method, followed by converting a single-layer PDF file into an image file, then using OCR software to recognize, and then directly using two-layer PDF software to retrieve the file.