BASALT · JOURNAL
Redacting immigration and visa documents
Immigration files carry identity documents in their most complete form: passport pages, biometric residence cards, birth and marriage certificates. They are also frequently shared with employers, landlords, schools and government agencies.
What comes out
Passport and document numbers, which are reusable identifiers. Biometric identifiers. Signatures, which are reproducible from an image. Dates and places of birth where not required. Home addresses. Sponsor and employer details where the recipient does not need them. Details of family members appearing on the same document.
Identity documents are photographs
A passport page in a file is an image, so redacting it means destroying pixels and re-encoding. A black rectangle drawn over a document number in an annotation layer is removed by the recipient in one operation, and passport numbers are exactly the kind of data that is valuable to whoever recovers it.
The status disclosure risk
The most serious risk in these files is often not a specific field but the fact of the matter itself. A document revealing that someone has applied for a particular status, or has a particular history, can expose them to harm in ways that a name and address alone would not.
That changes the analysis: the question is not only which fields to remove but whether this recipient should receive the document at all.
Third parties
Immigration documents routinely name people who are not the applicant: family members, sponsors, referees, previous employers. They are frequently left in because the document is thought of as being about one person.
Practical checks
Extract the text and search for document numbers, which often appear in more places than expected including headers and reference lines.
Read the metadata, which in documents scanned by an agency or produced by case management software can carry a case reference identifying the applicant.
Look at every image at full size in the output, because an image redaction failure is invisible to a text extraction.
Never upload these
Identity documents are the clearest case for local processing. A passport scan transmitted to a web based tool has left the applicant's control entirely, and for someone whose safety may depend on their status not being known, that is a serious matter rather than a policy technicality.
This is a description of common practice rather than legal advice. Obligations vary by jurisdiction and by the terms you are working under, and the authority that governs your work is the one to check with.
Frequently asked questions
What should be redacted from immigration documents?
Passport and document numbers, biometric identifiers, signatures, dates and places of birth where not required, home addresses, sponsor and employer details where not needed, and family members appearing on the same document.
How do I redact a passport scan?
It is an image, so the pixels must be destroyed and the image re-encoded. A black box drawn as an annotation is removed by the recipient in one click, leaving the document number fully visible.
What is the biggest risk in immigration document handling?
Often the fact of the matter rather than any single field. A document revealing someone's status or history can expose them to harm, which makes the question of whether a recipient should receive it at all as important as which fields to remove.
Is it acceptable to use an online tool for identity documents?
No. A passport scan transmitted to a web service has left the applicant's control, and for someone whose safety may depend on their status remaining private that is a serious matter rather than a technicality. Process locally.
Doing it in Basalt
Basalt is a native macOS PDF toolkit built around redaction that removes content rather than covering it. After writing a file it re-opens its own output with an independent parser, searches for the material again, and refuses to save if anything is found. It also strips metadata, XMP, attachments, embedded scripts and hidden layers as part of the same operation, and a separate Inspector reports what any PDF still hides, including documents Basalt did not create. Everything runs on your Mac: the engine holds no network entitlement at all, which macOS enforces at the code-signature level. A one time $29 licence covers up to three Macs, free for the first 24 hours. basaltformac.com, or brew install --cask chipmunk1101/tap/basalt.
Redaction that proves itself
Basalt destroys the content you mark, then re-opens the file it wrote and proves the content is gone before it saves anything. Your documents never leave your Mac.