Em Space and Indesign's Justification Settings

Hey, I ended up here since I am reading the same book. But I think I can clirify a bit your doubt with a different approach then other comments here but pretty much saying the same thing.

in the book Robert says that 1 unit of em is equivalent to the size of your type (type of which is usually measured in pt). So if your type is 12pt then 1 em of so type would be equivalent as 12pt in length - in other words 1 em = 100% of type size.

He also adds that a minimum word space would be 1 em devided by 5 (M/5), in other words 100% typesize/5 so 20% of such type size.

I hope I did not make it further confusing

Thank you! That clears it up. I didn't know that Indesign sets it automatically.

Thanks again,

Kristi

Hi,

I think you are simply making a small mathematical mistake.

Let's look at you example of 12 pt:

The rule says 1/5 of an em for minimum. em (approx.) is 12 pt, so you are right whe you say minimum is 12pt/5=2.4 pt, but not percent. 1/5 would be 20%. So your result is in points, not percentage: 12pt*1/5=12pt*0,2=2,4 pt.

But Indesign already does all these calculations for you with choosing an Adobe paragraph composer. All you have to do is to choose if you want to override the result.

100% in Indesign dialog box means optimal spacing calculated by Adobe paragraph composer for the current font size.

In InDesign the normal space is set up in Paragraph properties in Justification. 100 % is normal Word space, by default it is 80 % to 133 %.

InDesign uses the word space which is defined in the font, not what your book calculates.

I haven't read Bob's book, but I'd imagine the book is geared towards traditional typography, and not to InDesign specifically. The issue here is that he is referring to spacing in ems, while InDesign is using percentages of the actual spacebar character, which is determined by the individual font designers. If you want to use his formula, you will need to figure out what the default space is set to in ems for that type size, and calculate out from there.

Another recognized typography expert is Nigel French. His book, InDesign Type, covers typography with an eye specifically on InDesign, which you may find useful. He states that "a starting point for good word spacing is 100%, which is the width of the space band specified by the font designer." He suggests reducing the desired width to 90% for condensed type, light weights, etc. From there, look at the word spacing as it appears on the page and adjust the minimum and maximum values with the aim to reduce the word spacing while simultaneously reducing variations in the widths.