paper size

Paper is usually manufactured on a continuous basis, as huge rolls. Except for newsprint, which is normally used directly from such a roll, the product is generally unrolled and progressively cut into lesser entities, characteristically into very large sheets. These in turn can be used directly for artwork, used in a printery to produce a mosaic of printed pages that are folded, cut, then, if for a book, bound and usually trimmed, else they can be similarly processed by a paper supplier into the various sizes of general stationery. Whether a leaf of a book or a sheet of stationery, the size typically reflects a systematic repeated halving of a large sheet. The familiar terms quarto and octavo represent this process, carried out respectively twice, giving four sheets, and three times, giving eight sheets. While these terms are readily associated with particular sizes, e.g. quarto with 8½ in × 11 in, they are really relative terms applicable to any original sheet size, very many different sizes having been produced. The ‘demy’ is the full sheet that gives rise to the familiar ‘quarto’ (letter size in North America), of 17½ in × 22½ in. Foldings of the demy progress as shown in Table 35, the ratio repeating since any pair of consecutive folds produces like-shaped quarters of any beginning sheet. Less obviously, the alternating values are reciprocals relative to

. Were the initial proportions equal to that figure, i.e. 1.414~, the ratio of long side to short side of successive products would remain the same. Such a ratio, being an irrational number, is not precisely convenient in practice. The ISO values
[ISO 216:1975 Writing Paper and Certain Classes of Printed Matter in Trimmed Sizes - A Series and B Series] come as close as practicable, the reference ‘A’ full sheet of 1 square metre being 841 mm × 1 189 mm. The rounded-down theoretical related sizes of this ‘A Series’ are shown in Table 36, the ratios all effectively the same.

	in × in		mm × mm		Ratio
full sheet	17.5	22.5	444.5	571.5	1.286
folio	11.25	17.5	285.75	444.5	1.556
quarto (4to)	8.75	11.25	222.25	285.75	1.286
octavo (8vo)	5.625	8.75	142.875	222.25	1.556
16mo	4.375	5.625	111.125	142.875	1.286

	mm × mm	in × in
2A	1 189	1 682	46.8	66.2
A0 or A	841	1 189	33.1	46.8
A1	594	841	23.4	33.1
A2	420	594	16.5	23.4
A3	297	420	11.7	16.5
A4	210	297	8.2	11.7
A5	148	210	5.8	8.2
A6	105	148	4.1	5.8
A7	74	105	2.9	4.1

As can be seen, the A4 of this series is very close in size to the old British quarto and the North American letter size, being half an inch narrower and half an inch longer, a balanced adjustment to meet the


standard. Specified trimmed sizes in this A Series are the whole mm figures. Clearly this is incompatible, for the smaller sheets at least, with the realities of repeated halving, never mind real trimming. To allow for practicalities, larger sizes are specified for the base material, in the form of a general ‘RA Series’ for normal trimming, with RA0 being 860 mm × 1 220 mm, and a special ‘SRA Series’ that provides a greater trimming margin by having SRA0 at 900 mm × 1 280 mm.

The dimensions 841 mm × 1 189 mm of the parent ‘A’ sheet, were chosen to make it 1 m². The related ‘B Series’, related more to posters, and ‘C Series’, to envelopes, have similar rectangularity but parent areas of


m² = 1.413 8~ m² and


m² = 1.189 2~ m², giving different grid sizes, as shown in Table 37, the last of these being just comfortably larger than A4, its successors the same proportionally larger than A5 et seq., equally of A4 folded centrally once, twice, et seq. However, to meet the widely established practice of folding letters into thirds, there is also the special size: A fractional prefix can be used to indicate a sheet derived by fractioning the length, e.g. ¼A3 means 297 mm by 105 mm.

	mm × mm	in × in
B0	1 000	1 414	39.37	55.67
B4	250	353	9.84	13.90
C0	917	1 297	36.10	51.06
C4	229	324	9.02	12.76

	mm × mm	in × in
DL	108	219	4.25	8.62