When drawings are to be washed out for proofing or printing, the plate should first be thinly gummed up.
There are, or ought to be, three aims in the process of proofing and stiffening, all the three being of equal importance.
Raw rubber has been used to some extent for proofing purposes, as for the manufacture of material for hoods of motor-cars.
Kerned types are a source of trouble because of the ease with which these projections break off during composition, proofing, etc.
The proofing machines won't operate here either, of course, and so we need human personnel.
early 13c., preove "evidence to establish the fact of (something)," from Anglo-French preove, Old French prueve "proof, test, experience" (13c., Modern French preuve), from Late Latin proba "a proof," a back-formation from Latin probare "to prove" (see prove). "The devocalization of v to f ensued upon the loss of final e; cf. the relation of v and f in believe, belief, relieve, relief, behove, behoof, etc. [OED].
Meaning "act of proving" is early 14c. Meaning "act of testing or making trial of anything" is from late 14c., from influence of prove. Meaning "standard of strength of distilled liquor" is from 1705. In photography from 1855. Typographical sense of "trial impression to test type" is from c.1600. Numismatic sense of "coin struck to test a die" is from 1762; now mostly in reference to coins struck from highly polished dies, mainly for collectors.
Adjectival sense (proof against) is recorded from 1590s, from the noun in expressions such as proof of (mid-15c.), hence extended senses involving "tested power" in compounds such as fireproof (1630s), waterproof (1725), foolproof (1902), etc. Shakespeare has shame-proof.