What's wrong with Japanese B paper sizes?
What's a gnomon? What does this have to do with geometrical progressions?
I hoped you'd ask that question. Suppose you want a range of paper sizes: the most obvious way to pick them is so that they increase linearly. You might decide you want paper for printing photographs with a 2:3 aspect ratio, from 2x3 cm to 20x30 cm. By "linearly" we mean simply that the sides of the paper increase by the same amount in each step, so the obvious set is extremely easy to calculate: 2x3, 4x6, 6x9, 8x12, ... 18x27, 20x30. The trouble is that although the steps look the same, the sizes are crowded at the large end, while customers designing postage stamps will keep asking for sizes between 2x3 and 4x6.
The answer is to make the step proportions the same. e.g. x1.25: This is a geometric series... Trouble is, working backwards is easy for an arithmetic series, cuz we divide. How to do geo - logs figure 2x3
Then try logarithmic..
Perhaps inevitably, photo.net kept coming up as an example, naturally of a well designed site. As he says, somewhere, the trouble is that the websites you know the best are always the ones you built yourself. And this isn't egotism: photo.net (curious how I pronounce this "photo dot-net[rising tone]" while he seems to say "photodot[falling tone] net") is a fantastic resource for every decision you will ever have to make about buying camera equipment. Yet, again, its strength comes from a relatively subtle design point: the content is not just Immutable Truth written by an Expert, it's the collaborative suggestions of a community of contributors. (This is also why this "community" tag really is a useful description, and not just more hype.) Unfortunately, it seems impossible to describe the effectiveness of this approach to anyone who hasn't experienced it. In the questions afterwards, someone asked how you ensure that contributions are "correct", but of course this isn't the problem, since gross errors normally receive a barrage of correction. As Greenspun says, the real problem is keeping the questions in line.
And the paper?
B sizes ...
And the Japanese version
Baffled by copier in Xerox ... answer speculation ...