Comparative Measurements

Comparative measurement is the disciplined comparison of an object's quantifiable properties with suitable reference examples. It turns impressions such as "the proportions look wrong" or "this feels too light" into recorded observations: dimensions, mass, thickness, spacing, angles, ratios, repeated-feature frequency and, where justified, microscopic or specialist measurements.

Its value is not that a matching number authenticates an object. Measurement tests whether the object is physically consistent with the proposed maker, period, edition, variant, material and production method. It is often strong evidence for excluding an impossible attribution, useful supporting evidence for a plausible one and rarely sufficient on its own for positive authentication.

The central rule

A measurement does not say

"This object is genuine."

It can say

"For the property measured, by this method and against this reference group, the object is consistent - or inconsistent - with the proposed attribution."

Orientation

Why numbers help - and why they mislead

Visual comparison is vulnerable to scale, perspective, lighting, image distortion and expectation. Measurements force the collector to define what is being compared, but the apparent objectivity of a number can conceal weak methods and weak references.

Evidence

What was actually observed

A value, ratio, count or geometric relationship recorded from a defined feature using a stated method.

Meaning

Why the observation may matter

The difference may fit production tolerance, wear, material movement, restoration, alteration, reproduction or an incorrect attribution.

Collector risk

What happens when the two are confused

A genuine object may be rejected for harmless variation, while a precisely copied counterfeit may be accepted because one published number matches.

Collector scenario: the number matches but the object still feels wrong

A collector checks a figure against a published height and finds an almost exact match. That seems reassuring. Yet two trusted examples show a narrower base, thinner walls and a slightly lower emblem. The headline dimension agrees, but the internal geometry and mass do not share the same production logic.

The responsible conclusion is neither "genuine" nor "fake". The object is consistent in one easy-to-copy property and anomalous in several less obvious ones. Those anomalies should be remeasured, checked against a broader reference population and tested through material, tooling or construction evidence.

Define before measuring

The measurand: decide exactly what the number represents

In measurement science, the measurand is the quantity intended to be measured. The term matters because instructions such as 'measure the box' or 'check the thickness' are not reproducible.

A defensible instruction might be: maximum external width of the closed box, excluding loose shrink-wrap remnants, measured perpendicular to the long axis with a rigid rule. Another might be: centre-to-centre distance between the two upper attachment holes, measured on the reverse face.

Without that definition, two careful collectors can measure different physical points and believe they are comparing the same property.

Which physical points form the endpoints?

Is the value maximum, minimum, average or nominal?

Are tabs, bindings, rims or irregular projections included?

Is the object open, closed, assembled or dismantled?

Is a flexible object relaxed, flattened or under tension?

Are packaging, wrapping, sleeves or mounts included?

Is thickness taken at the edge, centre or several locations?

Are holes measured edge-to-edge or centre-to-centre?

Has a humidity-sensitive object been allowed to acclimatise?

Which units, repetitions and rounding rule will be used?

Measurement set

Measure the properties that can discriminate

The correct set depends on the proposed identity and the mechanism by which a genuine variant, alteration or counterfeit would differ. Easy measurements are not automatically useful measurements.

Overall dimensions

Use: Tests scale, trimming, shrinkage, distortion and component compatibility.

Examples: Height, width, depth, diameter, circumference and maximum or minimum span.

Caution: Easy to obtain, but often less diagnostic than internal relationships. Irregular edges and projecting tabs must be defined.

Mass and weight

Use: Tests material, construction, missing contents, hollow or solid form and replacement parts.

Examples: Coins, medals, sealed products, figures, mechanisms and component assemblies.

Caution: Interpret with dimensions and condition. Wear, corrosion, missing parts and added restoration material can alter the result.

Thickness and profile

Use: Can reveal stock changes, lamination, recasting, relining, added layers and substituted panels.

Examples: Paper, card, sheet metal, boards, walls, rims, covers and component sections.

Caution: Contact pressure can compress soft materials, while jaws can bridge curved or irregular surfaces.

Feature spacing

Use: Tests the internal geometry created by artwork, dies, moulds, fasteners and assembly systems.

Examples: Borders, lettering, holes, rivets, seams, logos, registration, pins, lugs and screw positions.

Caution: Record whether measurements are edge-to-edge, centre-to-centre or from a defined landmark.

Ratios and proportions

Use: Tests design relationships even when photographs or objects are not reproduced at the same scale.

Examples: Image-to-sheet width, rim-to-diameter, label-to-panel height and landmark-to-overall length.

Caution: Ratios are only robust when both dimensions are affected consistently; perspective and non-uniform resizing can corrupt them.

Angles, curvature and geometry

Use: Tests complex shapes that simple length measurements may miss.

Examples: Bevels, tapers, arcs, radii, symmetry, edge profiles and component orientation.

Caution: Damage, warping and perspective can imitate geometric mismatch. Complex profiles may require optical or 3D methods.

Frequency and counts

Use: Tests repeated manufactured structures and production rhythms.

Examples: Perforations, reeding, stitches, screen dots, grooves, teeth, threads and mould ribs.

Caution: State what was counted and over what distance. Holes, teeth, spaces and complete repetitions are not interchangeable conventions.

Microscopic dimensions

Use: Tests fine manufacturing, printing, plating and tooling features beyond unaided vision.

Examples: Line width, ink dots, relief height, fibres, particles, tool marks and plating thickness.

Caution: Magnification labels are not measurements. The imaging system must be calibrated against an appropriate scale.

Reference quality

A measurement is only as strong as its comparison population

A single authentic object establishes one possible value, not the full genuine range. Reference quality depends on provenance, variant matching, condition, sample size and compatibility of method.

Authoritative production specifications

Original drawings, mint specifications, printer records, packaging dielines and factory quality-control documents establish intended nominal dimensions. They may not reveal the full range actually produced.

Verified authentic objects

Well-provenanced, independently authenticated and minimally altered examples usually provide the best evidence of real-world variation, especially when measured using the same procedure.

Institutional catalogue records

Museum and archive dimensions can be valuable, but may be rounded, inherited from earlier records or recorded for collection management rather than forensic comparison.

Specialist publications and census data

Aggregated measurements may reveal ranges and clusters. Reliability depends on sample size, authentication quality, variant separation and whether the figures were independently measured.

Dealer, auction and marketplace listings

Treat as provisional. Measurements may be approximate, copied, transcribed incorrectly or taken from a different example than the one illustrated.

Uncalibrated photographs

Useful mainly for relational or proportional observations. Without a scale in the correct plane and controlled imaging, they do not normally support reliable absolute dimensions.

One example is not a population

A useful reference set includes several examples of the same edition or production state, separates known variants, records condition and alteration, and - where relevant - includes different batches, worn examples and common environmental distortion. Its purpose is to discover the genuine range, not to make every object conform to one favoured specimen.

Nominal value, observed value, production tolerance, population variation and measurement uncertainty are different ideas. Collapsing them into one catalogue number is one of the fastest routes to false certainty.

Uncertainty

Every measurement has a margin of doubt

Uncertainty is not an admission of incompetence. It is an honest description of how widely plausible values may be distributed around the reported result.

False certainty

Width: 152.4 mm

More defensible record

Width: 152.4 mm +/- 0.3 mm, measured with a steel rule

Instrument

Resolution, calibration, zero error, damaged jaws, unstable scales and display rounding all affect the reported value.

Object

Uneven edges, curvature, wear, corrosion, dirt, restoration, movement and material flexibility make the endpoint less certain.

Method

Different endpoints, orientations, contact pressure, positioning and inclusion rules can produce repeatable but incompatible results.

Environment

Temperature, humidity, tension, vibration and acclimatisation can change either the object or the measurement process.

Operator

Parallax, judgement of boundaries, handling technique, transcription and rounding can add variation even when the tool is sound.

Image system

Perspective, lens distortion, resizing, interpolation and an incorrectly placed scale can turn pixels into misleading pseudo-measurements.

Boundary judgement: near the range is not the same as beyond explanation

Suppose verified examples span 99.7-100.3 mm and the questioned object measures 100.2 mm +/- 0.2 mm. It is dimensionally consistent, but too close to the boundary for that measurement to discriminate strongly. A result of 103.1 mm +/- 0.2 mm is different: the discrepancy is much larger than both the method uncertainty and the observed authentic variation.

Even then, first challenge the reference data, variant assignment, condition and method. Strong exclusionary evidence is only strong after plausible alternative explanations have been tested.

Measurement quality

Accuracy, precision, repeatability and reproducibility are not synonyms

Accuracy

How closely the result approaches the accepted value. A result may repeat beautifully and still be wrong if the instrument or method is biased.

Precision

How closely repeated readings agree. Precision describes consistency, not truth.

Repeatability

Agreement under essentially the same conditions: same operator, tool, object, method and short time interval.

Reproducibility

Agreement when conditions change, such as another operator, instrument, day or laboratory.

A practical collector test

Measure the same feature three times.
Remove and reposition the instrument for each reading.
Record every value and the spread between them.
Ask another person to repeat the method when the result matters.

If one collector obtains 51.2, 51.2 and 51.3 mm while another obtains 50.5, 50.6 and 50.5 mm, both are individually repeatable but the method is not reproducible. They may be choosing different endpoints or applying different pressure.

Tools

Choose an instrument proportionate to the object and the decision

The right tool is not always the one with the finest display. Use the least invasive method capable of resolving the authentication question.

Steel rule

Suitable for: Books, posters, packaging, toys and larger components.

Strength: Simple, broad range and low contact pressure.

Risk or limit: Parallax and ambiguous endpoints; inadequate for very small tolerances.

Digital or vernier caliper

Suitable for: Coin diameter, component thickness, holes, edges and small rigid parts.

Strength: Inside, outside and depth measurements with useful resolution.

Risk or limit: Can scratch surfaces, compress soft material and create false confidence through extra decimal places.

Micrometer

Suitable for: Controlled thickness of robust sheet, wire and precision components.

Strength: Consistent small-scale measurement when the object tolerates contact.

Risk or limit: Contact force may deform or damage fragile paper, coatings, paint and soft surfaces.

Scale or balance

Suitable for: Coins, medals, components, sealed products and missing-content checks.

Strength: Fast screening of material or completeness when used with dimensional evidence.

Risk or limit: Drafts, vibration, an unsuitable capacity, wrong units or poor checks can undermine the result.

Calibrated microscope or optical comparator

Suitable for: Perforations, print structures, profiles, micro-lettering and tool marks.

Strength: Makes small feature relationships measurable rather than merely visible.

Risk or limit: Requires calibration and a clear definition of the measured feature.

Scanner, photogrammetry or 3D scan

Suitable for: Two-dimensional geometry, complex shapes, deformation and surface topology.

Strength: Can preserve a repeatable visual record and compare many landmarks.

Risk or limit: Scaling, distortion, processing and object-safety assumptions must be validated rather than presumed.

Low-risk action versus damaging intervention

Usually reasonable

Rigid-rule measurements without dragging across the surface
Weighing stable objects on a clean, padded or suitable platform
Non-contact photography with a correctly positioned scale
Repeated readings that do not require dismantling or pressure

Pause or escalate

Caliper or micrometer contact on fragile, painted or compressible surfaces
Dismantling sealed, rare or mechanically complex objects
Density tests involving immersion, liquids or unstable materials
Flattening, tensioning or forcing warped and brittle objects

Material and condition

Collectibles are not dimensionally inert

Before treating a discrepancy as evidence of manufacture, ask how the material, environment and history of the individual object could have changed it.

Paper, board and wood

Can expand, contract, curl and warp with humidity; fibre direction, previous wetting and trimming influence dimensions.

Leather and textiles

Can stretch, shrink, compress and distort through use, tension, moisture and treatment.

Plastics and rubber

May shrink, swell, creep, warp, lose plasticiser or deform under heat and load.

Metals

Wear, corrosion, bending, tooling and temperature can alter mass, edges and profiles.

Ceramics, glass and stone

Usually less humidity-responsive, but production irregularity, chips, grinding, polishing and restoration affect measured form.

Composite objects

Different materials can move at different rates, creating misalignment, separation and deformation that mimic manufacturing inconsistency.

Image measurement

Photographs can support measurement only when the image geometry is controlled

Pixels become physical evidence only when scale, plane, perspective, distortion and resizing are understood.

Defensible setup

Camera sensor parallel to the measured plane
Object not tilted or curved away from the camera
Scale in the same plane as the feature
Lens distortion corrected or shown to be negligible
Original file retained with enough resolution
Resizing, cropping and processing history documented

Common failure modes

A ruler lies on the table while the object is raised above it
Wide-angle distortion changes dimensions near the frame edge
A web image has been stretched differently in width and height
The object plane is angled, making one side appear shorter
A nominal scanner resolution is assumed to be exact everywhere
Ratios are calculated from a cropped or perspective-distorted image

A suitable conclusion may be: "The questioned logo occupies approximately 31% of the panel width, compared with 36-37% in the controlled reference images."

An unsuitable conclusion is: "The object is exactly 0.4 mm too short" when the image system cannot support that precision.

Interpretation

Compare differences, ratios, ranges and patterns - not isolated numbers

Direct difference

Record questioned value minus reference value and state whether the object is larger or smaller. Direction can matter diagnostically.

Percentage difference

Useful when scale changes. A 1 mm difference is substantial on a 10 mm feature and trivial on a one-metre object.

Ratio comparison

Tests internal relationships and can remain useful when absolute image scale differs, provided distortion is controlled.

Range comparison

Place the object against the observed minimum and maximum, while recognising that a small sample may not reveal true production limits.

Distribution

With enough examples, median, spread, clusters and outliers reveal whether values form one population or several.

Physical explanation

Statistical neatness does not identify the genuine group. Manufacturing, historical and material evidence must explain the pattern.

Diagnostic recognition

Measurement patterns that can change the authentication question

The most useful result is often not a single mismatch but a structured pattern that predicts how the object was made, altered or copied.

Uniform scale reduction

Most dimensions are smaller by a similar percentage. Possible explanations include mould shrinkage, copy casting, reduced artwork, material shrinkage or intentional miniaturisation.

Correct exterior, incorrect interior

The overall object matches, but artwork, holes, borders or internal landmarks do not. This can indicate redrawn artwork, replacement labels, counterfeit dies or a scan resized to fit.

Two dimensions agree; the third fails

Correct diameter but wrong thickness or mass, correct box face but wrong depth, or correct height but reduced cross-section may expose material or manufacturing differences.

Asymmetrical discrepancy

One side or region differs while the rest matches. Consider trimming, local repair, warping, misregistration, replacement parts, perspective or a genuine production miscut.

Repeated identical abnormalities

Several questioned objects share the same unusual dimensions and defects. They may descend from one counterfeit mould, die, scan or digital master.

Distinct measurement clusters

Groups form around different values. They may reflect factories, tooling, periods, export versions, authorised reprints, altered objects, counterfeit families or inconsistent methods.

Category application

What to measure changes with the collectible

The same principles apply across categories, but the discriminating properties, tolerances and condition effects are category-dependent.

Coins, tokens and medals

Potential measurements

Mass
Diameter
Thickness
Edge count and spacing
Rim and design positions

Interpretation: Read the measurements as a system. Wear can reduce mass, while a lower-density counterfeit may preserve diameter by increasing thickness.

Stamps and postal material

Potential measurements

Perforation gauge
Design dimensions
Margins
Overprint position
Watermark geometry

Interpretation: Separate original production variation from reperforation, trimming, paper distortion and altered overprints.

Trading cards and sports cards

Potential measurements

Overall size
Border widths
Corner radius
Stock thickness
Image and text position

Interpretation: Dimensions may reveal trimming, but factory cutting and off-centre printing must not be mistaken for later alteration.

Books, comics and ephemera

Potential measurements

Leaf and binding size
Text-block thickness
Margins
Leaf count
Staple or sewing positions

Interpretation: Distinguish edition-level dimensions from copy-specific binding, trimming, missing leaves, added material and repair.

Posters, prints and photographs

Potential measurements

Full sheet
Image area
Margins
Fold positions
Printer and registration marks

Interpretation: A published finished size may not equal the original untrimmed sheet. Mounting, trimming, relining and shrinkage alter the evidence.

Toys, models and figures

Potential measurements

Defined-pose height
Joint and socket sizes
Base diameter
Screw spacing
Wall thickness and component mass

Interpretation: Nominal scale is not a guarantee of exact anatomy. Tooling, casting shrinkage, replacement accessories and pose must be considered.

Ceramics and glass

Potential measurements

Rim and base diameter
Height
Wall thickness
Capacity
Handle and mould-seam position

Interpretation: Hand finishing, firing shrinkage, mould wear, grinding and restoration can produce legitimate or condition-related differences.

Jewellery, watches and mechanisms

Potential measurements

Case and movement size
Lug or link width
Screw placement
Gem dimensions
Component mass

Interpretation: Interchangeable parts make whole-object and component-level comparison equally important.

Packaging and sealed collectibles

Potential measurements

Panels and flaps
Seam width
Seal position
Blister geometry
Crimp spacing and contents mass

Interpretation: Packaging may expose reconstruction or resealing even when the enclosed object is genuine.

Limits

What comparative measurement cannot establish

Correct dimensions are compatible with authenticity, but they are also compatible with a precisely made copy.

Provenance

Date of manufacture by itself

Who made a signature

Whether original materials were assembled at the original time

Whether a later issue was authorised

Whether restoration is acceptable

Whether two matching objects came from the same batch

Whether a published specification is correct

Whether original tooling was used in the claimed period

Whether a dimensionally accurate copy is genuine

Measurement mimicry

Counterfeiters can deliberately reproduce public dimensions. Simple external size may therefore become less discriminating precisely because collectors publish it. Stronger evidence may lie in combinations of measurements, obscure internal geometry, manufacturing tolerances, microscopic relationships, material composition, tooling marks and features that cannot be copied faithfully from photographs.

A correct, easy-to-copy dimension should cause only a small increase in confidence. A correct combination of obscure relationships arising naturally from original tooling may deserve more weight.

Myth versus reality

Numbers do not remove judgement

Myth

The dimensions match, so the object is genuine.

Reality

Correct dimensions show dimensional consistency. A capable copyist can reproduce published measurements, and original tooling can sometimes be used outside the claimed context.

Myth

A digital display to 0.01 mm makes the result accurate to 0.01 mm.

Reality

Display resolution is not practical accuracy. Endpoint ambiguity, pressure, calibration, surface shape and operator technique may be much larger influences.

Myth

One authentic object defines the genuine size.

Reality

One example proves only that its value can occur. A defensible range requires a population that separates variants, batches, condition and method.

Myth

Any outlier is counterfeit.

Reality

An outlier can be mismeasured, damaged, restored, anomalous, an undocumented variant, an altered genuine object or a counterfeit. It is a trigger for investigation, not a verdict.

Collector workflow

A defensible comparative-measurement procedure

The process should be explicit enough for another careful person to understand, repeat and challenge.

Define the claim

Record the exact maker, period, edition, variant, material, production method, region and component state being tested.

Define the comparison group

Choose references that match that claim as closely as possible. Do not average together unlike versions merely to create a number.

Choose discriminating measurements

Measure properties connected to plausible explanations for authenticity, alteration or reproduction rather than collecting easy but irrelevant figures.

Write the method

Define endpoints, orientation, instrument, units, pressure or handling, environmental state, rounding and number of repetitions.

Check the instrument

Confirm zero and test against an appropriate known reference. Record the instrument used and any limitation relevant to the decision.

Measure repeatedly

Where feasible, remove and reposition the tool for at least three readings. Preserve the raw results rather than only the preferred number.

Photograph the setup

Show the measurement points, instrument placement, displayed result, object identifier and any scale or check reference.

Compare with the population

Use individual reference values, ranges, ratios, patterns and clusters. Do not mistake one nominal figure for the entire authentic population.

Test explanations

Consider production tolerance, material response, damage, restoration, variant status, counterfeit manufacture and measurement error.

Integrate other evidence

Combine measurements with materials, construction, tooling, printing, surfaces, provenance, known variation and specialist findings.

State a bounded conclusion

Say what the measurements support, contradict or leave unresolved. Avoid converting dimensional consistency into a claim of proven authenticity.

Example bounded conclusion

"The measured height, width and internal logo proportions fall within the range observed in six verified examples. Thickness is approximately 12% greater than that group and remains anomalous after repeated measurement. This does not prove the object counterfeit, but it weakens the proposed attribution and warrants material and construction analysis."

Documentation

Record enough detail for the measurement to survive future scrutiny

A useful record allows a later collector, specialist or buyer to understand what was measured, reproduce the method and separate raw evidence from interpretation.

Record field	What to capture
Object and claim	Identifier; exact edition, variant, date, material and production claim
Measurand	The precise property intended to be measured
Measurement points	Annotated photograph or diagram showing endpoints and orientation
Instrument	Type, model, resolution and identifying detail where relevant
Instrument check	Zero check, check weight, rule comparison or calibration reference
Object state	Assembled, dismantled, wrapped, relaxed, flattened, acclimatised or under tension
Conditions	Temperature, humidity or other relevant environmental factors
Raw readings	Every repositioned reading, not only an average or selected result
Reported result	Value, spread or estimated uncertainty and rounding convention
Reference group	Specific objects, specifications and individual comparison values
Condition factors	Wear, distortion, trimming, corrosion, repair, relining or restoration
Interpretation	Consistent, anomalous or indeterminate, with alternative explanations
Authentication weight	Screening, supporting, strong or exclusionary evidence
Record control	Examiner, date, images and later revisions

Evidence weighting

How much authentication weight should the result carry?

Strength depends on relevance, method, reference quality, uncertainty, reproducibility and whether the result has a credible physical explanation.

Weak

The result is too approximate, poorly referenced or methodologically uncontrolled to carry much authentication weight.

One approximate reading
An uncalibrated or unchecked tool
An online listing as the sole reference
An uncontrolled photograph
A comparison with the wrong variant

Moderate

The measurements are repeatable and relevant, but the reference population or discriminatory power remains limited.

Several repositioned readings
A documented procedure
Compatible reference examples
A discrepancy larger than obvious reading error
A pattern across connected dimensions

Strong

The discrepancy or match is reproducible, well referenced and physically connected to the proposed manufacturing explanation.

Multiple authenticated references
Calibrated or validated instruments
Difference well outside known variation and uncertainty
Corroboration from material or construction evidence
A coherent mechanism explaining the result

Very strong exclusionary

The claimed attribution becomes physically impossible or irreconcilable unless the reference, method, variant or condition explanation is wrong.

Hole spacing cannot fit the documented assembly
Density conflicts with the claimed solid metal
An allegedly untrimmed sheet is smaller than its printed image
A repeated proportional reduction fits copy casting
Dimensions cannot accommodate the claimed component

Confidence

Let diagnostic power determine how far confidence moves

Correct and easy to copy

Only a small increase in confidence. Public dimensions are often deliberately imitated.

Correct obscure combination

A larger increase may be justified when several relationships arise naturally from original tooling or manufacture.

Minor unexplained mismatch

A caution rather than a rejection, especially near the limits of the method or reference population.

Large mismatch with a reliable constraint

A substantial decrease in confidence after variant, condition, reference and measurement error have been excluded.

Multiple independent mismatches

Potentially strong evidence against the attribution when they point toward one coherent alternative manufacture.

Mismatch explained by documented change

Little or no negative authentication effect once damage, restoration or known variation adequately explains it.

Specialist threshold

Escalate when the measurement requires expertise or could change the object

Seek a qualified specialist when the conclusion depends on very small tolerances, calibrated microscopy, density or material testing, 3D comparison, dismantling, controlled contact force, fragile or highly valuable surfaces, or a reference population that only a category specialist can validate.

Specialist involvement is also warranted when the result may materially affect a high-value purchase, legal dispute, insurance claim, institutional accession or public attribution. The collector's role is then to preserve the object, the raw readings, the setup photographs and the chain of reasoning - not to force a verdict from inadequate equipment.

Key takeaways

Define the measurand before touching the object.
Choose measurements that test a real authentication question.
Use a matched reference population, not one convenient example.
Separate nominal values, observed variation and measurement uncertainty.
Prefer patterns, ratios and connected dimensions over a single easy match.
Account for condition, material behaviour and restoration before interpreting discrepancy.
Use the least invasive tool capable of resolving the question.
Document raw readings, method, references and alternative explanations.
Treat dimensional consistency as supporting evidence, not proof of authenticity.
Escalate when precision, risk or claim consequence exceeds ordinary collector practice.

Final collector rule

The purpose of comparative measurement is not to make authentication look scientific by adding decimal places.

It is to make comparison explicit, testable, repeatable, documented, proportionate and open to correction. The sound conclusion is rarely "the dimensions match, therefore it is genuine."

It is more often: "The object is dimensionally consistent with verified examples under the stated procedure, and no measurement-based contradiction to the attribution was found" - or, where warranted, "The discrepancy exceeds the known reference variation and the uncertainty of the procedure, making the proposed attribution materially less likely."

Continue learning

Limits of Comparison

Return to the limits that prevent comparison from becoming proof by resemblance.

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Back to Comparative Analysis

Review the full comparative-analysis sequence and its connected authentication methods.

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Comparative Imagery

Continue to the use of photographs, scans and image relationships as comparison evidence.

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