Perforation gauge is the number of perforation teeth or holes in two centimeters.
Identification rule: record what is visible before assigning a catalog number or value.
What to record
- Count intervals over a long clean edge.
- Measure both horizontal and vertical sides.
- Record compound gauges separately.
What commonly causes mistakes
- Scans may be resized or distorted.
- Missing teeth do not change the underlying gauge.
- Reperforation can imitate a scarcer gauge.
A practical research sequence
- Identify the issue family.
- Measure with a trusted physical or transparent gauge.
- Compare hole shape, alignment, and edge fibers.
- Check all sides and compare with catalog listings.
Condition and value
Value depends on exact identity, condition, centering, gum or cancellation, faults, certification, demand, and a defensible comparison set. A famous design does not automatically make an individual example rare.
Perforation estimate calculator
Formula: intervals × 20 ÷ measured millimeters. Use this as a check, not a substitute for a proper gauge.
Compare current collector listings
Use listings to study descriptions, scans, certificates, and market supply. Asking prices are not completed-sale evidence.
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