PDF Glossary

Cryptographic signature proving integrity and signer authenticity.

Cryptographic protection applied to document content and permissions.

Visible text or image overlay applied to pages.

Permanent removal of sensitive content from a document.

Reducing image pixel dimensions to lower file size and processing cost.

Machine-readable text content embedded alongside scanned page imagery.

Optical Character Recognition that turns scan images into machine-readable text.

Techniques used to reduce file size while balancing quality.

Dots per inch, a common density measure in scanning and printing.

PDF arranged for fast web viewing by prioritizing early-page access.

Descriptive document data such as title, author, and timestamps.

Likelihood that a document behaves consistently across tools and viewers.

Font programs stored in a document so text renders consistently.

Document model preserving exact page appearance regardless of device.

Embedding only used glyphs instead of complete font files.

Fallback behavior when requested fonts are unavailable.

Structured markup language used in many document and data formats.

Navigational outline entries for jumping through document sections.

Appending changes to an existing PDF without rewriting whole file.

PDF index structure mapping object locations.

PDF feature that packs multiple objects together for efficiency.

Color profile data ensuring predictable color interpretation across devices.

Visual property allowing partial see-through layering.

Structural markup used to represent document semantics.

PDF containing semantic tags for structure and assistive reading.

Declared compliance level for a standards profile.

Design and document practices enabling equal access for all users.

Software or hardware used by people with disabilities to consume content.

Document stability and reproducibility over long retention periods.

Practices for maintaining long-term usability of digital files.

Document-level restrictions such as printing or copying limits.

PDF page box defining visible page region in viewers.

Print-oriented page box indicating bleed area.

Physical page boundary of the PDF page.

Intended final trimmed page size in print workflows.

Layer-like PDF mechanism for toggleable content visibility.

PDF variant combining multiple structural and compatibility characteristics.

URL fragment syntax targeting specific locations in a PDF.

Page description language historically related to print and PDF lineage.

Image correction step that straightens tilted scanned pages.

Score indicating OCR engine certainty in recognized text.

Small preview image representing a document or page.

PDF where text can be found and copied, often via OCR.

PDF where interactive and transparency elements are baked into static content.

CSS rules that control page layout when HTML is rendered for print/PDF.

Native PDF form technology based on PDF form fields.

Password required to open an encrypted PDF document.

Sequence of PDF drawing/text operators that render page content.

Password controlling permissions in a protected PDF, such as printing or editing.

Logical sequence assistive technologies use to read document content.

XML Forms Architecture used in some dynamic PDF forms.

Strong symmetric encryption algorithm commonly used to protect PDF content.

The relationship between original size and compressed output size.

Image-specific size reduction methods used inside and outside PDFs.

Structured notes or markup attached to PDF content.

Tagged PDF hierarchy that defines semantic structure like headings and lists.

Compression that preserves all original data.

XML-based office document standard behind DOCX, XLSX, and PPTX.

Alternate term for optional content groups in PDF.

Mapping from glyphs to Unicode code points, often via ToUnicode data in PDFs.

Text alternative that describes meaningful non-text elements like images.

Compression that permanently discards some detail for smaller files.

Declared PDF specification version used by a file.

Validation process checking whether a file meets target output constraints.

Hierarchical PDF structure that organizes pages and inherited attributes.

How content is split and ordered across pages in a document.

Modern ISO PDF specification generation (ISO 32000-2).

Compressed cross-reference representation introduced in newer PDF versions.

Term used in some workflows for rights or restricted variants and references.

Preparation stage before printing, including validation, color checks, and output conditioning.

Pixel or dot density describing visual detail level.

Removing hidden data, metadata, scripts, or attachments from documents.

Converting images into black-and-white pixels for OCR and compression workflows.

Controlled conversion between device color spaces to keep visual appearance consistent.

Raster Image Processor converting page descriptions to printable rasters.

Handling many files in one automated operation.

Cutoff score used to accept or reject OCR-detected characters/words.

JPEG-based compression filter used for many embedded images in PDFs.

Framework for issuing, managing, and validating digital certificates.

Conversion of vector or text content into fixed pixel images.

Server-side file processing instead of local execution.

Character mapping resource used by PDFs and CJK fonts to map encoded text.

Common PDF compression filter based on DEFLATE.

Online Certificate Status Protocol for real-time certificate revocation checks.

Pixel-level decision method used in binarization to separate foreground text from background.

Graphics represented by geometric primitives instead of pixels.

Published list of revoked certificates that should no longer be trusted.

Ability for text or layout to adapt to screen size or editing environment.

Increasing image pixel dimensions by interpolation after original capture.

Ordered trust path from signer certificate to trusted root authority.

Bi-level image compression method used in scanned monochrome content.

Signature validation strategy preserving trust evidence over long periods.

Reusable internal target in a PDF for links and navigation jumps.

Logical page numbering metadata that can differ from physical page index.

Process of detecting and exporting table structures from documents.

Extensible metadata framework commonly embedded in PDFs.

Fax-era bi-level image compression commonly used for monochrome document scans.

JPEG 2000-based image compression filter used in some PDF image objects.

Identifier for each indirect object in a PDF file structure.

Trusted time assertion proving when data existed or was signed.

Standard certificate format used in most PKI signature ecosystems.

Fonts and encoding behavior for Chinese, Japanese, and Korean scripts.

Version counter paired with object numbers in PDF object references.

Container specification used to package structured XML parts and relationships.

Color-conversion strategy that prioritizes appearance under gamut changes.

Interactive instruction in PDFs that opens pages, views, or linked resources.

Embedded file payload stored inside a PDF document.

Decorative/non-semantic PDF content excluded from logical reading order.

Internet standard describing content types and multipart message bodies.

Print behavior where one color is printed on top of another without knockout.

Print behavior where underlying color is removed before placing new objects.

PDF container that bundles multiple files while preserving originals.

Predefined color ink (often Pantone-style) used in professional printing.

Technique using dot patterns to simulate continuous-tone imagery in print.

Print compensation technique that adjusts overlapping colors to avoid registration gaps.