Engagement · Provenance

Greyline Provenance

A structured assessment of whether a contested recording, image or file is what it is presented to be.

What This Is

What this is.


Where a recording or image is disputed, the question is rarely answerable with a simple yes or no. A finding needs to explain what was tested and why it points where it does.

The assessment examines integrity and origin: file metadata, container and encoding history, and content credentials where present. It also reviews evidence of re-encoding or editing, device and codec consistency, and internal plausibility. Findings are expressed as consistent with, not consistent with, or indeterminate, with the reasoning and its limits stated in full.

Two engagement modes are available, Standard and Litigation, set out below.

Service Categories

Where Provenance applies.


1. Image Verification

Applied to a contested photograph, screenshot, or still image.

Verification AreaWhat We Examine
Metadata and EXIF dataCamera model, capture date, GPS data, and editing software signatures
Reverse image searchPrior appearances, stock or stolen content, and earlier versions
Compression and artefact analysisSigns of re-encoding, cloning, or splicing
Lighting and shadow consistencyPhysical plausibility of light sources and shadows
Facial and object consistencyAnatomical or geometric inconsistencies associated with synthetic generation
Content credentialsEmbedded provenance signals where present

2. Video Verification

Applied to a contested video clip or recorded call.

Verification AreaWhat We Examine
Frame-by-frame analysisTemporal consistency across frames
Compression historyEvidence of re-encoding, transcoding, or multiple exports
Audio-visual synchronisationAlignment between lip movement and the audio track
Motion and physics plausibilityConsistency of movement with physical expectation
Source and container metadataCodec, container format, and editing software traces
Synthesis indicator screeningKnown artefacts associated with face-swap and synthetic media tooling

3. Audio Verification

Applied to a contested voice recording, voicemail, or call.

Verification AreaWhat We Examine
Spectral analysisFrequency patterns inconsistent with natural speech or splicing
Voice sample comparisonComparison against a genuine voice sample of the claimed speaker, where available
Background consistencyAmbient noise and acoustic environment plausibility
Compression artefactsEvidence of re-recording or synthetic generation
Vishing pattern cross-referenceThe circumstances checked against known social engineering scripts

Where a submission is a suspicious call or voice message rather than a standalone clip, the circumstances are cross-referenced against documented vishing patterns as a matter of course, since a genuine voice can still be used in a scripted deception.

Engagement Modes

Two ways this runs.


Standard

Deliverable
Written assessment with reasoning and stated limitations
Use
Internal decision-making, HR, insurance, pre-action
Availability for questions
Written clarification

Litigation

Deliverable
Report prepared to the standard required of expert evidence, including duty declaration, range of opinion and statement of truth
Use
Filed evidence, rebuttal of an opponent's exhibit
Availability for questions
Availability to answer questions on the report
What Is Included

What is included.


Assessment of file integrity, metadata and encoding history

Review of content credentials and provenance signals where present

Analysis of editing, re-encoding and compression artefacts

Assessment of internal consistency, including acoustic and physical plausibility

Written findings with reasoning, confidence and stated limitations

What Is Not Included

What is not included.


A binary determination that content is or is not artificially generated

Speaker identification or voice attribution to a named individual

Recovery, extraction or acquisition of files from a device

Assessment of re-recorded or screen-captured material where original files are unavailable, unless expressly agreed in scope

Who This Is For

Who this is for.


Solicitors and barristers in family, employment and civil matters, insurers, and in-house counsel most commonly instruct this work. Individuals responding to a contested recording also instruct it directly.

How It Runs

How it runs.


  1. Source files are submitted through a confidential inquiry, along with the question the assessment needs to answer.

  2. The engagement mode, Standard or Litigation, is confirmed at scoping, along with turnaround.

  3. Metadata, encoding history, content credentials and internal consistency are examined against the original files.

  4. Findings are reviewed by the principal and expressed as consistent with, not consistent with, or indeterminate, with reasoning stated in full.

  5. The report is delivered. Written clarification, or availability to answer questions under the Litigation mode, follows afterward.

Illustrative Examples

How this looks in practice.


The following are illustrative examples of how Provenance is typically used, not accounts of specific client engagements.

Contested recording in a family matter

A party to a family dispute submits an audio recording said to capture an admission by the other side. Provenance assesses the file for splicing, re-recording and compression artefacts before either party relies on it in negotiation or proceedings.

Workplace investigation

An employer receives a video alleged to show misconduct by an employee. Provenance assesses the file's integrity and internal consistency before it informs a disciplinary decision.

Insurance claim review

An insurer receives photographic evidence supporting a claim. Provenance checks the metadata, compression history and internal consistency of the image before the claim is assessed further.

Rebutting an opponent's expert evidence

An opposing party serves an expert report relying on a contested image. Under the Litigation mode, Provenance independently re-examines the same file and tests the opposing report's methodology and conclusions.

Cadence and Deliverable

How this is delivered.


Turnaround for a single-file assessment is three working days from receipt of usable source material, not from the date of instruction. Volume or format complexity may extend this; any extension is agreed in writing before work proceeds.

Shape
Fixed scope
Cadence
Single engagement
Deliverable
Written authenticity assessment, Standard or Litigation mode
Review
Principal-reviewed before release
Report Structure

What the report contains.


SectionContent
Instructions and issues addressedThe specific questions the examination was asked to address
Scope of the examinationWhat was examined, what was not, and which engagement mode applies
Summary of conclusionsA short-form answer to each question, ahead of the full reasoning
Exhibit scheduleEvery item examined, with format, size and hash on receipt
Provenance of the materialHow each exhibit reached this firm, and what that means for what can be concluded
Chain of custodyFull handling record from receipt to examination
MethodologyThe examination sequence followed and the standards it aligns with
FindingsWhat was observed in each exhibit, by analysis stream
Automated detector outputsClassifier results, with published error rates and their limitations
EvaluationEvery anomaly weighed against the innocent explanations considered for it
ConclusionsThe instructed questions answered, in defined terminology
What would change these conclusionsThe further material that would allow a firmer answer
LimitationsWhat the examination does, and does not, establish
DeclarationThe examiner's confirmations, including independence and completeness
Specimen Report

See a full specimen report.


The specimen below shows a full Standard-mode report, illustrating the report structure above section by section. The case, the exhibits, the parties and every finding are fictitious.

Download the specimen report (PDF) →
Limitations and Scope

Limitations and scope.


Assessment of contested media carries real limits, stated here rather than left implicit.

  • Detection tooling is probabilistic, and its reliability degrades with compression, re-encoding and platform transmission. An indeterminate finding is a legitimate outcome and is reported as such.
  • Assessment quality depends on access to the original file. Screenshots, forwarded copies and screen recordings materially limit what can be established.
  • Turnaround runs from receipt of usable source material, not from the date of instruction.
  • The Litigation mode describes the standard the report is prepared to. It does not, on its own, state the preparing analyst's expert accreditation or courtroom experience; that is confirmed separately where it is relevant to a specific instruction.
Ready to Begin

Submit a confidential inquiry.

Every enquiry is reviewed by an analyst and routed to a scoping call, a written scope is confirmed before any work begins.