E - essay, a proposed design

HBg - horizontal broken gum, a horizontal diamond pattern impressed in the gum to prevent curling.

imp, imperf - imperforate

NG - no gum

NM - negative maker's proof, a true printer's proof

p - proof, usually imperforate

pcp - progressive color proof, usually a set of 7 stages showing colors separately and in

combinations, leading up to the complete design.

P4S - perforated on all four sides

perf 12:00x12 - horiz rows of perfs are perf 12, with 2 larger diameter perf holes at intervals;

usually 11 regular perf 12 holes are between pairs of larger holes.

(PH) - Photo in center section

PM - perforated margin

pm - printer's mark. Since 1936 printer's used a tiny letter on seal #56, on sheets of 100, to identify

their product.; "E" Eureka Specialty Printing Co., "S" Strobridge Litho. Co. 1930-58, Specialty

Printers of America 1975-92 "D" Edwards and Deutsch Litho. Co., "U" U.S. Printing and Litho.

Co., "F" Fleming-Potter Co., etc.

r.9, roul.9 - roulette 9

S - Spring issue

SE - straight edge

SE4S - straight edge on all 4 sides of a sheet

Sg - smooth gum

SqBg - square broken gum - a square pattern impressed in the gum to prevent curling.

T - test seal, usually a design experiment

TB - tuberculosis

UK - unknown printer

UL - Union Label, like printer's marks, these can be used to identify sheets.

VBg - vertical broken gum, a vertical diamond pattern impressed in the gum to prevent curling.

VM - varying margin; a margin made when a cut separates a perforated press sheet into smaller

sheets or panes. Depending on where the knife cut chances to fall, such a margin will be a narrow PM, SE, or perforated edge. From 1932-62 Eureka sheets have a VM on two sides of the sheet.

x - sheet