Editors can get almost manically attached to certain trim sizes, and often appear to find it difficult to accept that this or that book is just as good a book if it appears in a trim size different from the one they had visualized. This same effect of loving what we first thought of can be seen in cover design too. How often have you been told that that jacket looks awful: the laser print is what we want (although the laser print is of course a grossly distorted version of the original it represents)? But we publishers think we “know” that this sort of book should have this trim size, while that sort should have another trim. Often this is driven by nothing more than a desire that when this book lines up on a shelf with other books we have published, they should make a neat row. But there’s only one organization which would ever shelve its books like that — the publisher themselves. So trim size decisions, especially those calling for a non-standard trim size, may in effect be based on nothing more than a wish that the shelves in our office should look neat!

Now of course there are some “conventional” trim sizes, but they are just that: conventions. We are perfectly content to read different editions of a book in different trim sizes. If War and Peace was being published today for the first time, there’s not a publisher in the land who’d do it in any size other than 6⅛” x 9¼”, but as you know you have been perfectly content to read it as a 5½” x 8¼” or 5″ x 8″ or 4⅛” x 7″ as a mass market paperback.

Trim sizes came from somewhere — they are not just dimensions dreamed up by some designer which other designers looked at and though good. They come from printing presses: sheet-fed printing presses. Making a printing press is not that easy and press manufacturers will take care to make their presses in the sizes required by their customers. At some point presses for book work stabilized into a few standard sizes, which meant that printers could offer publishers attractive pricing based on this or that sheet size. This meant that instead of printing a novel as a 6¼” x 9½” book, say, which would have been perfectly doable, publishers would opt to save money by going for 6⅛” x 9¼” because there were lots of presses out there which could do that size efficiently and thus cheaply. To print the larger format you’d have had to use a bigger press, perhaps with more paper spoilage, and this press would be priced at a level calculated to divert most cost-conscious customers to the smaller one. Thus did standard sizes develop — driven by the economics of press manufacture.

It’s no coincidence that 25″ x 38″ is the standard sheet size in America used to calculate the basis weight of papers. If you lay out an imposition for a 4 x 4 array of 6⅛” x 9¼” pages, you will find it will fill an area 25″ x 38″. Remember that a trim allowance of ⅛” has to be left for each page (that’ll be ¼” where two pages meet). Across the top the measurements will be ⅛” + 6⅛” + 6⅛” + ¼” + 6⅛” + 6⅛” + ⅛” (which adds up to 25″. There’s no ⅛” trim allowance within the two pairs of pages — that’s where the gutter is, and you need to keep that, untrimmed.) Down the long side of the sheet the measurements will be ⅛” + 9¼” + ¼” + 9¼” + ¼” + 9¼” + ¼” + 9¼” + ⅛” which totals 38″. (Remember, you want ⅛” top and bottom and on the outer edge after folding, thus the internal distances are ¼”.

Scan 10

So these trim sizes didn’t come down from the mountain fixed and permanent. They evolved. I remember in the late 70s or maybe the early 80s when Random House standardized their books thoroughly. R. R. Donnelly gave then pricing for 6⅛” x 9¼” books, using a couple of papers and half a dozen covering materials which meant effectively that all their books were done that way. They almost couldn’t afford not to. Of course by then the work was being done on web presses, which unsurprisingly when they were developed would follow the conventional trim sizes evolved for the sheet-fed presses which had preceded them.

When I first started in book production there were many more non-standard size presses available in the industry. If you thought that a book might use a slightly different format (maybe to accommodate some art, or to fit into the pocket) you might design a page to fit the press. Starting with the maximum sheet size of the press, you could juggle the number of pages-to-view and the page dimensions, to come up with an economical way to deliver an unusual book. Of course what you did had to be imposed so that it was possible to fold it to make a sig.

If you are puzzled as to why I show some of the pages one way up and others in reverse, see my earlier post on Imposition.