View source for Printer's key

{{short description|Typesetting practice}}
{{for|the mathematical concept|Number line}}
{{Use shortened footnotes|date=August 2022}} 
[[Image:Lotrtitlepage.jpg|thumb|right|300px|A copyright page with the printer's key underlined. This version of the book is the eighteenth printing.]]
The {{strong|printer's key}}, also known as the {{strong|number line}}, is a line of text printed on a book's [[Edition notice|copyright page]] (often the [[verso]] of the [[title page]], especially in English-language publishing) used to indicate the [[Edition (book)#Print run|print run]] of the particular edition. The convention appears in titles published around the middle of the {{nobr|20th century;}} it became common practice after 1970.{{sfn|Boutell|1949|p=26|loc={{nobr|§ "Thomas}} Y. Crowell Company" {{nobr|¶ "1947}} Statement"}}{{sfn|Ahearn|Ahearn|2011|loc=[https://books.google.com/books?id=oUMxWVOI_goC&lpg=PA57&pg=RA1-PA1991 {{nobr|§ "First}} Edition Identification"]|ps=. {{retrieved|access-date=2022-08-24|via=[[Google Books]]|note={{font|size=111%|text=limited preview}}}}}}

An example follows:

{| border="1" cellspacing="0" cellpadding="5" align="center"
! 1 2 3 4 5 6 7 8 9 10
|}

This is how the printer's key may appear in the first print run of a book. In this common example numbers are removed with subsequent printings, so if "1" is seen then the book is the first printing of that edition. If it is the second printing then the "1" is removed, meaning that the lowest number seen will be "2".{{sfn|''Stop Counterfeit Books''|2022}}

==Examples==
Usually, the printer's key is a series of non-repeating characters (numbers or letters). However its structure or presentation is not uniform, as shown in the following examples.{{sfnm|1a1=Rennicks|1y=2021|1loc={{nobr|§ "How}} Can You Tell if a Book is a First Edition?"|2a1=Ahearn|2a2=Ahearn|2y=2011|2loc=[https://books.google.com/books?id=oUMxWVOI_goC&lpg=PA57&pg=PA1998-IA153 "First Edition Identification By Publisher"]|ps=. {{retrieved|access-date=2022-08-24|via=[[Google Books]]|note={{font|size=111%|text=limited preview}}}}}}

The series may be in descending or ascending sequence:

{| border="1" cellspacing="0" cellpadding="5" align="center"
! 10 9 8 7 6 5 4 3 2 1
|}

{| border="1" cellspacing="0" cellpadding="5" align="center"
! 1 2 3 4 5 6 7 8 9 10
|}

{| border="1" cellspacing="0" cellpadding="5" align="center"
!a b c d e f g h i j k
|}

In some cases, rather than follow in unidirectional sequence, the numbers may alternate from left to right:

{| border="1" cellspacing="0" cellpadding="5" align="center"
!2 4 6 8 10 9 7 5 3 1
|}

In other cases, number lines may include a date segment consisting of two-digit consecutive-year codes:

{| border="1" cellspacing="0" cellpadding="5" align="center"
! 2 3 4 5 6 &nbsp;&nbsp; 73 72 71 70 
|}

This indicates a second printing (or {{em|second impression}}) and that it occurred in 1970. Specifically, it is the particular [[imprint (trade name)|imprint]]'s second impression of the edition.

When the publisher outsources the printing to a contractor, a code identifying the contracting printer may occasionally be shown:

{| border="1" cellspacing="0" cellpadding="5" align="center"
! 3 4 5 6 7 8 9 10 &nbsp; APC &nbsp; 00 99 98 97 96 
|}

The hypothetical printer's key above means
* third printing
* printed in 1996
* contracted to Acme Printing Corporation.

The examples above are not exhaustive; other key configurations may be used, especially in editions published following the advent of [[digital printing]] and [[print on demand]].{{sfn|''Stop Counterfeit Books''|2022|loc=§ "D"}}

==First edition vs. first printing==
Bibliographers usually define a [[Edition (book)#First edition|first edition]] as all printings from substantially the same type setting, no matter how many printings are done. Book collectors tend to define ''first edition'' as the first printing of the first edition.{{sfn|Boutell|1949|p=[ix]|loc={{nobr|§ "Explanatory}} note to the Original Edition"}}{{sfn|Carter|1995|pp=84{{en dash}}85|loc={{nobr|§ "Edition}} and Impression"}}

==Why key characters are removed rather than added==
With each successive reprint, the publisher needs to instruct the printer to change the impression character. In practice, if the plates (in [[offset printing]]) have been kept, a character can be erased, but nothing can be added. In this arrangement, all the printer need do is "rub off" the last character in sequence. Changing only the outer character requires the fewest possible changes to the page of characters, which means the smallest possible charge to the publisher.{{sfn|Boutell|1949|p=26|loc={{nobr|§ "Thomas}} Y. Crowell Company" {{nobr|¶ "1947}} Statement"}} In the days of [[letterpress printing]], where each character was a metal block, all the printer had to do was to pick out the relevant block(s) from the "sheet"; the remaining stack of blocks, which had been laboriously laid out when the page was first set up, could then be inked for the reprint.{{sfn|Levy|Mole|2017|pp=17{{en dash}}22|loc={{nobr|§ "Making}} Printed Books"}} In the case of a [[Linotype machine|Linotype]] slug, the lowest character could be filed off and the slug reused.{{refn|name=theory|In theory; linotype operators sometimes used [[File (tool)|files]] (and other tools) in order to make fine adjustments.{{sfnm|1a1=''The Inland Printer''|1y=1899|1p=745|2a1=Stedman|2y=1918}}}} For offset printing with metal [[Offset printing#Plates|plates]], the character can be erased without damaging the rest of the plate. In each case, the change is minimal.{{sfn|Duncan|Smyth|2019|p=64}}{{refn|name=date|Although a number line's date segment (if it exists) follows the changes in the print run sequence, it may not necessarily change at the same rate or the same time.}}

==Digital typesetting and printing==
In modern [[computer to plate]] typesetting and digital printing the entire printer's key may be easily re-imaged (instead of reset by erasing or removing individual characters). This allows additional key configurations.{{sfn|''Stop Counterfeit Books''|2022|loc=§ "D"}}

==Notes==
{{reflist}}

==References==
<!--Alphabetically by contributor/author/editor, or else section/chapter/title; then by date/year; editor- or parser-inserted text formatting (e.g. quotation marks around titles) ignored.-->
{{refbegin}}

* {{cite book|author1-last=Ahearn|author1-first=Allen|author2-last=Ahearn|author2-first=Patricia|year=2011|orig-year=originally published 1991. New York: [[G. P. Putnam's Sons]]|url=https://books.google.com/books?id=oUMxWVOI_goC|url-access=limited|title=Collected books: the guide to identification and values|edition=4th|type=[[ebook]]|location=[[Comus, Maryland]]|publisher=Quill & Brush Press|isbn=978-1-8830-6014-5|name-list-style=amp|access-date=2022-08-10|via=[[Google Books]]}}

* {{cite book|author-last=Boutell|author-first=Henry S.|editor-last=Boutell|editor-first=Roger|year=1949|orig-year=originally published 1928. London: [[Elkin Mathews]]|title=First editions of today and how to tell them|url=https://archive.org/details/firsteditionsoft013431mbp|edition=3rd revised & enlarged|location=Berkeley & Los Angeles|publisher=[[University of California Press]]|lccn=50000048|oclc=1196280655|via=[[Internet Archive]]}}

* {{cite book|author-last=Carter|author-first=John|author-link=John Carter (writer)|year=1995|orig-year=originally published 1952. London: [[Rupert Hart-Davis]]|title=ABC for book collectors|url=https://archive.org/details/abcforbookcollec0000cart_w6t3|url-access=registration|edition=7th corrected|others=Corrections, additions and Introduction by [[Nicolas Barker|Barker, Nicolas]]|location=[[Newcastle, Delaware]]|publisher=[[Oak Knoll Press]]|isbn=9781884718052|via=[[Internet Archive]]}}

* {{cite book|editor1-last=Duncan|editor1-first=Dennis|editor2-last=Smyth|editor2-first=Adam|year=2019|title=Book parts|url=https://books.google.com/books?id=FCeeDwAAQBAJ|edition=1st|publisher=[[Oxford University Press]]|isbn=9780192579416|access-date=2022-08-10|name-list-style=amp|url-access=limited|via=[[Google Books]]}}

* {{cite web|ref={{sfnref|Stop Counterfeit Books|2022}}|author=<!--Not specified.-->|year=2022|title=Identifying a book's print run|url=https://stopcounterfeitbooks.com/resources/identifying-a-books-print-run/|website=Stop Counterfeit Books|publisher=[[Cengage]] et al. {{interp|book-publisher consortium}}|archive-url=https://web.archive.org/web/20220803033359/https://stopcounterfeitbooks.com/resources/identifying-a-books-print-run/|archive-date=2022-08-03|access-date=2022-08-06|via=[[Wayback Machine]]}}

* {{cite book|author1-last=Levy|author1-first=Michelle|author2-last=Mole|author2-first=Tom|year=2017|url=https://books.google.com/books?id=iwJbDwAAQBAJ|url-access=limited|title=The Broadview introduction to book history|edition=1st|type=[[paperback]]|location=[[Peterborough, Ontario]]|publisher=[[Broadview Press]]|isbn=9781554810871|name-list-style=amp|access-date=2022-08-11|via=[[Google Books]]}}

* {{cite magazine|ref={{sfnref|The Inland Printer|1899}}|author=<!--Not specified, see quote.-->|date=March 1899|title=Machine Composition Notes and Queries|url=https://books.google.com/books?id=g_ooAAAAYAAJ&pg=PA744|magazine=[[The Inland Printer]]|volume=22|issue=6|pages=744{{en dash}}746|quote-page=744|location=Chicago|quote={{interp|Section byline:}} Conducted by an expert.|oclc=714712112|access-date=2022-08-14|url-access=registration|via=[[Google Books]]}}

* {{cite web|author-last=Rennicks|author-first=Rich|date=17 December 2021|title=Identifying first editions|url=https://www.abaa.org/blog/post/identifying-first-editions|department=The New Antiquarian {{interp|blog}}|website=Antiquarian & Rare Books|location=New York|publisher=[[ABAA]]|archive-url=https://web.archive.org/web/20220103051644/https://www.abaa.org/blog/post/identifying-first-editions|archive-date=2022-01-03|access-date=2022-08-11|via=[[Wayback Machine]]}}

* {{cite magazine|author-last=Stedman|author-first=E. C.|date=March 1918|title=Filing Combinations|department=Hints for Operators and Machinists|url=https://books.google.com/books?id=X4XnAAAAMAAJ&pg=PA110|magazine=The Linotype Bulletin|volume=14|issue=7|page=110|location=New York|publisher=[[Mergenthaler Linotype Company]]|oclc=608103572|access-date=2023-10-08|url-access=registration|via=[[Google Books]]}}
{{refend}}

[[Category:Book design]]
[[Category:Typesetting]]