5 ms·

Which standard A4? (Which might be the problem.)

vanderZwan 3y ago
Show me a paper standard other than ISO 216, aka the international standard for paper size, that uses "A4" as the indicator for its default letter size.
- Cu3PO42 3y ago
  DIN 476 does use the same indicators. Of course that's just the original German standard that ISO 216 was based on and defines the exact same sizes, so it really doesn't matter. (Also it is superseded by DIN EN ISO 216, which is just ISO 216 backported.)
  - vanderZwan 3y ago
    Making sure we are technically correct is appreciated, thank you. But yes, that's a bit of a "structural vs nominal typing" distinction, and we seem to agree that a "structural typing" interpretation makes most sense here.
KeplerBoy 3y ago
210 x 297 mm.
- mgdlbp 3y ago
  This thread nerd-sniped me into looking up the exact definition of the dimensions. Neither standard gives the formula used to obtain the specified sizes (for A4, precisely as above, ±2 mm). But what's interesting is that we can tell from the rounded values that it is _not_ the geometric sequence that the stated principles imply, x(n) = 1000 * 2^(-1/4 - n/2) y(n) = 1000 * 2^( 1/4 - n/2) y(0) = x(-1) = 1189,2 would map to the 1189 mm long side of A0 and short side of 2A0 in the standard; y(1) = x(0) = 840,9 to 841 mm; and y(2) = x(1) = 594,6 to 594 mm -- inconsistent with any common rounding scheme. This also rules out evaluation of the recursive form with intermediate rounding, and/or starting with the approximations 1,414; 0,841; and 1,189 as written in the standard. Instead, a form that _is_ consistent is: x(0) = 841 = round(1000 / sqrt(sqrt(2))) y(0) = 1189 = round(1000 * sqrt(sqrt(2))) x(n) = floor(y(n-1) / 2) y(n) = x(n-1) Which makes sense - once A0 has been calculated, only halving and doubling are needed to determine the other sizes. B0 is even easier to memorize: 1000 mm x 1414 mm
  - occamrazor 3y ago
    That’s exactly how itvwas calculated. A0 is defined to have the right proportions, rounded to 1mm. The smaller formatsround always down, because this way it‘s possible to make two A(n*1) sheets by cutting an An sheet in two halves and possibly cutting away a thin stripe from the long side.
sokoloff 3y ago
The ISO 216 A4. What other A4 standard is there?

Show me a paper standard other than ISO 216, aka the international standard for paper size, that uses "A4" as the indicator for its default letter size.

Cu3PO42 3y ago
DIN 476 does use the same indicators. Of course that's just the original German standard that ISO 216 was based on and defines the exact same sizes, so it really doesn't matter. (Also it is superseded by DIN EN ISO 216, which is just ISO 216 backported.)
- vanderZwan 3y ago
  Making sure we are technically correct is appreciated, thank you. But yes, that's a bit of a "structural vs nominal typing" distinction, and we seem to agree that a "structural typing" interpretation makes most sense here.

KeplerBoy 3y ago

210 x 297 mm.

mgdlbp 3y ago
This thread nerd-sniped me into looking up the exact definition of the dimensions. Neither standard gives the formula used to obtain the specified sizes (for A4, precisely as above, ±2 mm). But what's interesting is that we can tell from the rounded values that it is _not_ the geometric sequence that the stated principles imply, x(n) = 1000 * 2^(-1/4 - n/2) y(n) = 1000 * 2^( 1/4 - n/2) y(0) = x(-1) = 1189,2 would map to the 1189 mm long side of A0 and short side of 2A0 in the standard; y(1) = x(0) = 840,9 to 841 mm; and y(2) = x(1) = 594,6 to 594 mm -- inconsistent with any common rounding scheme. This also rules out evaluation of the recursive form with intermediate rounding, and/or starting with the approximations 1,414; 0,841; and 1,189 as written in the standard. Instead, a form that _is_ consistent is: x(0) = 841 = round(1000 / sqrt(sqrt(2))) y(0) = 1189 = round(1000 * sqrt(sqrt(2))) x(n) = floor(y(n-1) / 2) y(n) = x(n-1) Which makes sense - once A0 has been calculated, only halving and doubling are needed to determine the other sizes. B0 is even easier to memorize: 1000 mm x 1414 mm
- occamrazor 3y ago
  That’s exactly how itvwas calculated. A0 is defined to have the right proportions, rounded to 1mm. The smaller formatsround always down, because this way it‘s possible to make two A(n*1) sheets by cutting an An sheet in two halves and possibly cutting away a thin stripe from the long side.

sokoloff 3y ago

The ISO 216 A4. What other A4 standard is there?