Annotations, Markups and Measurements
Spark distinguishes three classes of page objects. All three are stored as annotations in the PDF, but they behave differently in the UI.
Annotations (reviewer markups)
| Type | Examples | Typical use |
|---|---|---|
| Text markup | Highlight, Underline, Strikethrough, Squiggly | Marking text passages in OCR'd or native-text PDFs |
| Shapes | Rectangle, Circle, Polygon, Triangle, Star, Hexagon, Cloud, etc. | Calling out regions; 30+ built-in templates |
| Lines | Line, Arrow, Double Arrow, Polyline | Pointing, linking, sketching |
| Text notes | Text Box, Sticky Note, Text Callout | Written comments |
| Visual | Freehand | Pen-style sketching |
| Stamps | Approved, Draft, Custom stamps | Approval / status |
| Signatures | Drawn / imported signatures | Sign-off |
| Attachments | File Attachment, Sound | Embed related files |
All reviewer annotations share the same selection model: click to select, drag handles to transform, right-click for context menu, Delete to remove.
Measurements
Measurements also live on the page but compute real-world dimensions based on a calibrated scale. Types:
- Distance (point-to-point)
- Perimeter (polyline closed or open)
- Area (polygon)
- Rectangle / Circle area and perimeter
- Count markers (tally objects)
Measurements require a one-time calibration per document (see 05.1). Once calibrated, all measurement values are in the chosen units (mm, cm, m, inches, feet) and persist with the PDF.
Redactions
Redactions are annotations with a permanent-removal workflow. Two states:
- Marked for redaction (reversible) — a labelled overlay showing what will be removed.
- Applied redactions (permanent) — the underlying text and image content is actually removed from the PDF.
Apply redactions with a clear one-way step from the Redact menu. See 03.8 for the full redaction workflow.
Form Fields
Form fields are NOT reviewer annotations — they are first-class interactive PDF elements (text inputs, checkboxes, radio buttons, dropdowns). Spark edits them in place but does not let you add new form fields (use a dedicated form designer for that).
Which One Do I Want?
| Intent | Pick |
|---|---|
| Emphasise a word or sentence | Text markup (Highlight / Underline) |
| Flag a region without measuring it | Shape annotation (Rectangle / Cloud) |
| Explain something in writing | Sticky Note (small icon) or Text Box (visible) |
| Mark a revision / change area | Cloud (outward or inward bumps) |
| Give a measurement for real-world dimension | Measurement tool (after calibration) |
| Tally objects (chairs, lights, etc.) | Count marker |
| Remove sensitive content | Redaction |
What Gets Saved
When you Save (Ctrl+S), Spark writes all annotations and measurements into the PDF's annotation layer. Most PDF viewers can read these, though advanced features (cloud direction, measurement calibration) are Spark-specific extensions stored in custom PDF keys and may appear as plain shapes in other viewers.