Epreuves generales des caracteres
The pattern
This still is filed under Specimen as proof.
Define
A specimen (type, material, finish) is shown so the product proves itself under comparison.
Mechanism
Controlled display. Same conditions, side by side, no adjective required. The sample is the sentence.
Verdict
Buyers choose by eye or by hand and we can put the real thing in front of them.
Why it works
As a historical artifact, the blank flyleaf serves as a protective barrier and sets an expectation of age and authenticity, though it lacks direct marketing value.
Steal this when
When establishing a sense of antiquity, authenticity, or a protective physical buffer in a high-quality bound volume.