Papyrology (Paper-Study and Paper Manufacturing) Terms

Basic paper stock descriptions: size (h x w in inches for US or centimeters for the rest of the world); weight per ream of 500 sheets (in pounds for US or grams for the rest of the world)

Laid papers (made by hand using wire and deckle paper moulds): mould side (rougher, showing chain lines/watermarks) and felt side (smoother) [later parchment = hair side and flesh side]).
Laid paper manufacturing team: Vatman (Fr. Plongeur); Coucher; and sometimes Layer or Layboy.  (Circular spots visible in laid paper, caused by water drops hitting wet sheets, are called "vatman's tears.")  Usual speed of work = 1500 sheets per team per day (roughly 200 sheets per hour for a 12-hour day, about 2 sheets per minute).  (Compare "pressman's token," routinely said to be 250 single sided sheets per hour or 125 perfected sheets, 1500 perfected sheets per 12-hour day.)
Laid paper distinguishing marks: chain lines (roughly 1 inch apart); wirelines (perpendicular to chain lines, about a millimeter apart); tranchefiles (outermost chain lines); watermarks and (sometimes) countermarks).
Deckle: the frame fitting over the mould to hold down the outer edges of a paper "stuff" being formed into a sheet.
Deckle edge: thin feathery paper squeezed beneath the deckle at the outer edges of a laid sheet, usually trimmed off in binding to present a smooth surface, especially before dying or gilding.
Grain: the direction of the paper's fibers; paper folds best across the grain (perpendicular) and tears easiest with the grain.
Cockle, curl, and wave: rippled or bulging of paper due to water damage or poor manufacturing.
Collate (v.) and collation (n.): to gather sections of signatures together for binding, or to count those signatures and record them for "desbib" of the edition.
Four-color process: multiple impressions on the same sheet in cyan (blue), magenta (red), yellow, and black ink to create full-color images and text.
Color separation: breaking up a page image or type setting into portions to be printed in multiple colors in separate impressions or press runs.
Color bars: printed bars or dots of ink in four colors set outside the text area to aid print registration and proper ink density.
Register/registration: allignment of colored ink impressions on a multi-color page, or allignment of type lines on both sides of a perfected leaf to prevent "show-through" from either side.
Perfecting: printing the verso of an already-printed recto leaf to complete it.
Onionskin: lightweight paper used as tissue guards for full page images (e.g., woodblock or engraving prints) to prevent offset to facing pages, or used to make copies of correspondence.  (Also see "carbon paper").
Shives; unprocessed plant particles found in paper, especially early laid papers (e.g., flax stems, seeds, leaves).
Tack: pulling power fo wet ink that can cause "picking," splitting of paper or pulling off chunks that stick to printing type, other sheets, etc.  (vs. "flow," ink's relative liquidity)
Tooth: slight roughness of paper's surface conducive to inking.