Analysis of information sources in references of the Wikipedia article "Space (punctuation)" in English language version.
5.11 Spacing and Punctuation: Space once after all punctuation as follows: after commas, colons, and semicolons; after punctuation marks at the end of sentences; after periods that separate parts of a reference citation; and after the periods of the initials in personal names (e.g., J. R. Zhang). Exception: Do not use space after internal periods in abbreviations (e.g., a.m, i.e., U.S.)
In typewritten (as distinct from typeset) material, it was customary to place two spaces after a colon, semicolon, full stop or other sentence closing punctuation. Programs for word processing and desktop publishing offer more sophisticated, variable spacing, so this practice of double spacing is now avoided because it can create distracting gaps on a page.
If you are working on documents that will be printed without any intervention from a compositor (e.g., documents produced on the office laser printer), you will have to carefully scrutinize every piece of punctuation to be sure that the document contains the correct character (see table 5). You should also delete any extra wordspacing before and after punctuation marks. The conventions are: One space follows sentence-ending punctuation mark (period, question mark, or exclamation point). One space follows comma, colon, or semicolon ...
The view at CMOS is that there is no reason for two spaces after a period in published work. Some people, however—my colleagues included—prefer it, relegating this preference to their personal correspondence and notes. I've noticed in old American books printed in the few decades before and after the turn of the twentieth century (ca. 1870–1930 at least) that there seemed to be a trend in publishing to use extra space (sometimes quite a bit of it) after periods. And many people were taught to use that extra space in typing class (I was). But introducing two spaces after the period causes problems: (1) it is inefficient, requiring an extra keystroke for every sentence; (2) even if a program is set to automatically put an extra space after a period, such automation is never foolproof; (3) there is no proof that an extra space actually improves readability—as your comment suggests, it's probably just a matter of familiarity (Who knows? perhaps it's actually more efficient to read with less regard for sentences as individual units of thought—many centuries ago, for example in ancient Greece, there were no spaces even between words, and no punctuation); (4) two spaces are harder to control for than one in electronic documents (I find that the earmark of a document that imposes a two-space rule is a smattering of instances of both three spaces and one space after a period, and two spaces in the middle of sentences); and (5) two spaces can cause problems with line breaks in certain programs. So, in our efficient, modern world, I think there is no room for two spaces after a period. In the opinion of this particular copyeditor, this is a good thing.
A single justified word space will be used between sentences. This applies to all types of composition.
A single justified word space will be used between sentences. This applies to all types of composition.
Rule 1. With a computer, use only one space following periods, commas, semicolons, colons, exclamation points, question marks, and quotation marks. The space needed after these punctuation marks is proportioned automatically. With some typewriters and word processors, follow ending punctuation with two spaces when using a fixed-pitch font.
Publications in the United States today usually have the same spacing after a punctuation mark as between words on the same line. Since word processors make available the same fonts used by typesetters for printed works, many writers, influenced by the look of typeset publications, now leave only one space after a concluding punctuation mark. In addition, most publishers' guidelines for preparing electronic manuscripts ask authors to type only the spaces that are to appear in print.
Publications in the United States today usually have the same spacing after a punctuation mark as between words on the same line. Since word processors make available the same fonts used by typesetters for printed works, many writers, influenced by the look of typeset publications, now leave only one space after a concluding punctuation mark. In addition, most publishers' guidelines for preparing electronic manuscripts ask authors to type only the spaces that are to appear in print.
Rule 1. With a computer, use only one space following periods, commas, semicolons, colons, exclamation points, question marks, and quotation marks. The space needed after these punctuation marks is proportioned automatically. With some typewriters and word processors, follow ending punctuation with two spaces when using a fixed-pitch font.
A single justified word space will be used between sentences. This applies to all types of composition.
Publications in the United States today usually have the same spacing after a punctuation mark as between words on the same line. Since word processors make available the same fonts used by typesetters for printed works, many writers, influenced by the look of typeset publications, now leave only one space after a concluding punctuation mark. In addition, most publishers' guidelines for preparing electronic manuscripts ask authors to type only the spaces that are to appear in print.
Publications in the United States today usually have the same spacing after a punctuation mark as between words on the same line. Since word processors make available the same fonts used by typesetters for printed works, many writers, influenced by the look of typeset publications, now leave only one space after a concluding punctuation mark. In addition, most publishers' guidelines for preparing electronic manuscripts ask authors to type only the spaces that are to appear in print.
The view at CMOS is that there is no reason for two spaces after a period in published work. Some people, however—my colleagues included—prefer it, relegating this preference to their personal correspondence and notes. I've noticed in old American books printed in the few decades before and after the turn of the twentieth century (ca. 1870–1930 at least) that there seemed to be a trend in publishing to use extra space (sometimes quite a bit of it) after periods. And many people were taught to use that extra space in typing class (I was). But introducing two spaces after the period causes problems: (1) it is inefficient, requiring an extra keystroke for every sentence; (2) even if a program is set to automatically put an extra space after a period, such automation is never foolproof; (3) there is no proof that an extra space actually improves readability—as your comment suggests, it's probably just a matter of familiarity (Who knows? perhaps it's actually more efficient to read with less regard for sentences as individual units of thought—many centuries ago, for example in ancient Greece, there were no spaces even between words, and no punctuation); (4) two spaces are harder to control for than one in electronic documents (I find that the earmark of a document that imposes a two-space rule is a smattering of instances of both three spaces and one space after a period, and two spaces in the middle of sentences); and (5) two spaces can cause problems with line breaks in certain programs. So, in our efficient, modern world, I think there is no room for two spaces after a period. In the opinion of this particular copyeditor, this is a good thing.
In typewritten (as distinct from typeset) material, it was customary to place two spaces after a colon, semicolon, full stop or other sentence closing punctuation. Programs for word processing and desktop publishing offer more sophisticated, variable spacing, so this practice of double spacing is now avoided because it can create distracting gaps on a page.
