PDF terms explained simply

Browser processing means the file is handled locally by the browser for supported workflows.

Example: LiftPDF can merge supported PDFs without uploading them to a backend conversion queue.

Compression reduces file size by storing document data more efficiently or reducing heavy content.

Example: An image-heavy PDF may need stronger image compression than a text-only PDF.

DPI means dots per inch and is often used to describe print or scan density.

Example: A higher scan DPI can produce a sharper but larger image-based PDF.

Delete pages means removing unwanted pages while keeping the rest of the PDF.

Example: Delete blank scan pages before sending a document.

Encryption protects file content so the document cannot be opened without the required password or key.

Example: A protected PDF should ask for a password in Chrome PDF Viewer or Adobe Acrobat.

Extract pages means saving selected pages from a PDF into a new file.

Example: Extract pages 2, 5 and 8 from a report.

JPEG is a common lossy image format used for photos and camera images.

Example: A phone photo saved as JPEG can be converted into a PDF page.

JPG is the common file extension for JPEG images, often used for photos and scans.

Example: Use JPG to PDF when document photos should become a single PDF.

Lossless compression reduces file size without discarding original data.

Example: Some PNG compression is lossless, preserving sharp edges.

Lossy compression reduces file size by discarding some data, which can affect visual quality.

Example: Strong JPG compression can create artifacts or blur.

Metadata is information stored about a file, such as title, author, creation date or software history.

Example: Safe compression may remove or minimize metadata while preserving pages.

Merge PDF means combining multiple PDF files into one document.

Example: Merge a contract, appendix and cover page into one PDF packet.

OCR means optical character recognition. It converts text visible in an image into selectable text.

Example: A scanned PDF needs OCR before PDF to Text can extract words from the page image.

PDF is a document format designed to preserve page layout across devices, apps and operating systems.

Example: A contract sent as a PDF should keep the same page order and appearance on Windows, Mac and mobile.

PDF/A is an archival PDF standard intended for long-term preservation with embedded resources.

Example: An archive may request PDF/A so the document remains readable years later.

Password protection means a PDF requires a password to open or modify it, depending on the protection settings.

Example: A client document may be protected before being emailed.

A page range describes selected pages, such as 1-3, 5 or 7-10.

Example: Use 1,3,5-8 to export pages 1, 3, 5, 6, 7 and 8.

PNG is a raster image format commonly used for screenshots, diagrams and transparent images.

Example: A PNG screenshot can be converted to PDF for easier sharing.

A raster image is made of pixels. JPG, PNG and WEBP are common raster image formats.

Example: A scanned PDF page is often a raster image inside a PDF file.

Resolution describes the amount of image detail, commonly measured in pixels.

Example: A low-resolution JPG may look blurry when placed on a large PDF page.

Reorder pages means changing the sequence of pages inside a PDF.

Example: Move the signature page after the final contract page.

Split PDF means dividing a PDF into ranges or separate output files.

Example: Split every page of a 10-page document into separate PDFs.

Selectable text is real text in a PDF that can be highlighted, copied or extracted.

Example: PDF to Text works when the PDF contains selectable text.

A scanned PDF usually contains images of pages rather than real text objects.

Example: A photographed book page saved as PDF may require OCR before text extraction.

A vector image uses shapes and paths instead of fixed pixels, so it can scale cleanly.

Example: Logos and diagrams may use vector graphics inside a PDF.

WEBP is a modern image format designed for efficient web images.

Example: Images to PDF can combine WEBP with JPG and PNG files.

A watermark is visible text or an image placed on document pages.

Example: Add a draft watermark before sending a PDF for review.

WebAssembly is a browser technology that lets compiled code run efficiently on the web.

Example: QPDF WASM helps LiftPDF perform real PDF encryption and decryption in the browser.