Document Lexicon.

The global standard for data encryption, using a 256-bit key to transform PDF data into unreadable noise, essentially unbreakable by brute force.

The process of adding supplementary information (comments, highlights, shapes) to a PDF without changing the underlying static content.

An image processing technique that reduces the resolution of an image to shrink PDF file size while maintaining high visual fidelity.

The subtractive color model used in color printing. Unlike RGB (light), CMYK is optimized for physical ink on paper.

The internal index of a PDF that maps every object to its exact byte location in the file. A corrupt XRef is the most common cause of 'Broken' PDFs.

A cryptographic 'seal' placed on a PDF that ensures the document hasn't been modified since it was signed and identifies the signer via a private key.

A measure of spatial printing or video dot density. Higher DPI results in sharper images but larger PDF file sizes.

The process of including full font data inside the PDF file, ensuring the document looks the same on computers that don't have that font installed.

The process of merging multiple layers of a PDF (like checkboxes and text fields) into a single, static image layer that cannot be edited.

A range of shades of gray from white to black, used in PDFs to reduce color ink usage and decrease file size.

A set of data that characterizes a color input or output device, used to ensure color consistency across different screens and printers.

A specialized bi-level image compression standard used in PDFs primarily to shrink the size of scanned black-and-white documents.

An optimization that organizes a PDF file so the first page can be displayed in a browser while the rest of the file continues to download.

A method of reducing file size that allows the original data to be perfectly reconstructed without any loss of quality.

A method of reducing file size by discarding information that is less perceptible to the human eye, resulting in a permanent loss of detail.

Invisible data stored inside a PDF, such as the author's name, creation date, and software version used to generate the file.

The use of AI to convert an image of text (like a scan) into searchable and selectable digital text.

An ISO-standardized version of PDF specialized for use in the archiving and long-term preservation of digital documents.

A subset of the PDF standard specialized for graphics exchange in print production, ensuring high-fidelity color and font consistency.

The framework of roles and policies used to create, manage, and revoke digital certificates used for PDF signing and encryption.

The ability of the PDF format to maintain its visual appearance regardless of the operating system, device, or software used to open it.

The process of converting vector graphics (perfect lines) into a grid of pixels. Scaling a rasterized image results in pixelation.

The permanent and irreversible deletion of sensitive information from a PDF. Unlike 'blacking out,' true redaction wipes the underlying data.

A security credential required to open and view a PDF, which triggers the file's primary encryption mechanism.

Images defined by mathematical points and paths rather than pixels, allowing for infinite scalability without loss of clarity.