Determining a Vertical Rythym for Your Rational Grid

Posted on October 13, 2013


Figuring Fonts

In “How to Construct a Rational Grid for a Book,” I delved into typography. That example was theoretical and used misleading terminology to correctly build the grid in InDesign. This will show you how to calculate your typography correctly in the real world of Adobe products. From the original tutorial on setting up a grid, the font + leading must equal a number that divides evenly into 240. Or another way of looking at it is find numbers that divide evenly into 240, and then divide them up into font size + leading. So we saw we can divide 240 by evenly 2,3, 4 ,5, 6,  8 , 10 , 12 , 15, 16, 20, 24, 30, 40, 48, 96, 120. and get whole numbers.

How you define “leading” is important

InDesign Note: Now typically “leading” is the space between lines, but in InDesign they use that as the space from one baseline to another. So for Indesign, the leading must divide into 240. This really messed me up when I was first communicating with my designer.  I was talking the green space and InDesign was talking the blue.

Fonts2Let’s just call it “line height” must go into 240 evenly.

So your normal line height adds up to 11+12 =23. A good rule of thumb is that the lineheight should be 120% to 150%  font size. A 12 pt font with 50% leading adds up to 18, which is not one of the numbers. But a 10 pt font with 50% is 15 which works, as does 12 pt with 33% leading adding to 15, or 11 pt font with 37% adding to 15.

Let’s say we pick 11. With a total line height of 15. Your current is 23, which seems way off, or at least a bunch of white space. If we need that much space I would have it add to 20 or 24.

Caption could be 9 and 6 for 15 also, which might make sense for the long lengths he has.

Then the next multiple for the H2, skipping 16 as being too close, will be 20 or 24. A 15 pt font with a total line height of 20 gives us a 1.333 ratio. As does an 18 pt font with a total line height of 24. Your current heading 2 is 26 so it is just off.

Then H1s can be either 30 or 40. If we use 23 pt font for a line height of 30, that gives us a 1.3 ratio.

The Exception

Chapter header is a little different.  Let’s assume the top of  that is flush with the top margin. Therefore for the vertical rhythm here we want to put the space after the chapter, or else we have to have a special paragraph style for the first paragraph of each chapter.

You have to think of this one  just a little differently (I think, there are other ways to do it, like establish a first paragraph style etc.)

Chapter title
Space after chapter title

For Example

Just for discussion say its 36+12 for  a total line height of 48. Here the first paragraph from the chapter already has the line spacing. If you keep your 35 font and have a total line height of 48, then you have  13 pts of leading + the 3 from the normal for 16.  If that’s not enough you can play with it, change the first paragraph to be a special case, etc..
Just randomly it looks like in this example we could use:

  • Caption 9/6
  • Normal 11/4
  • Heading 2 15/5
  • Heading 1 23/7
  • Chapter Header 35/13

Which I’ve set up in the featured image.
And something in me really likes that 9,11, 15, 23, 35 odd number progression. You will have to play with it and see and if you have questions please let me know.

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