Why Proportional Fonts Break PDF Redaction Boxes, And How Pen. Code § 1054.2 Discovery Redaction Actually Works
Inside the glyph-width geometry bug that leaves trailing digits exposed in police reports, plus the statutory checklist for California criminal discovery redaction.
1. The Proportional Glyph Trap in Law Enforcement PDFs
Most modern computer-aided dispatch (CAD) printouts and police narrative PDFs use proportional sans-serif or serif fonts like Helvetica, Arial, or Times New Roman. When a PDF stores an entire line as a single text run, such as 'WITNESS: MARIA GOMEZ (DOB: 04/22/1994) / CDL (C7654321)', uppercase letters like 'W', 'M', and 'G' occupy more than three times the horizontal width of narrow characters like 'i', 'l', ':', or spaces.
Any redaction tool that estimates bounding boxes using uniform character-count ratios (startIndex / totalChars) systematically drifts leftward after uppercase prefixes, leaving the last two or three digits of a Social Security number, date of birth, or California Driver's License exposed outside the black box.
Defense counsel may not disclose the address or telephone number of a victim or witness to the defendant or defendant's family (§ 1054.2), and confidential informant identities remain privileged under Evid. Code § 1041 unless ordered disclosed by the court.
2. Sub-Run Glyph Measurement + Rasterized Pixel Flattening
Redact Master v5.0 eliminates horizontal box drift by disabling text-run combination in PDF.js (disableCombineTextItems: true), measuring exact proportional character advances using font-matched glyph metric tables and canvas text measurement, and applying asymmetric right-edge safety padding on numeric identifiers.
Equally important is forensic flattening: drawing a black rectangle annotation over vector PDF text without rasterizing the page leaves the underlying ASCII characters selectable via Ctrl+C. Flattening redacted pages into fresh pixel bitmaps strips the underlying vector glyphs completely, though counsel should note that flattened redacted pages are non-searchable images unless re-OCR'd after flattening.
- Keep Confidential Informants (Evid. Code § 1041), Victim/Witness Residences, Workplaces, Phones, and Minor Schools (Pen. Code § 1054.2) ON by default.
- Keep Defendant, Law Enforcement Officers, and the Primary Caption Case Number unredacted while redacting 3rd-party witness DVRO or CI probation docket numbers.
- Leave vehicle license plates unredacted by default in Fourth Amendment traffic-stop suppression discovery unless third-party privacy requires masking.
- Export the statutory Redaction Audit Log (.txt) alongside your flattened PDF to document Pen. Code § 1054.2 compliance.
