A few questions here... Em, en and thin spaces pros needed! :-)
Here is my situation :
I always use InDesign to do my type so I learned the shortcut for thin space and this is what I use. Back when I was in College, I was taught to put 1/4th of an em (quart de cadratin) before ! or ? (in french) and if I remember well, we'd do it by putting 25% in the horizontal scale for a normal space in Illustrator. This now makes no more sense to me as I read not too long ago that the thin space in InDesign is 1/8th of an em and not 1/4th. So according to what I learned, "espace fine" would not be the same thing as "thin space"... but the 1/8th of an em looks fine before ? and !... All the other designers I know use the same shortcut...are we ALL wrong or is the school wrong?! Neither option seems good to me :-)
I'm now the one teaching type (at the same school, 10 years later) and currently using a colleague's notes and something else seems wrong. I read in the theory normally given to the class that a normal space is a "demi-cadratin" so half an em (en). I know there is no way I'm typing an en-space each time I hit the space bar, it looks way smaller than the en spaces I use sometimes in InDesign. So okay, can someone tell me what's the width for a "normal" space? (I know it can be variable but it's not an en, is it?!)
The students work in Illustrator for now so I need to show them how to do their thin space in Illustrator. The method taught now instead of changing the horizontal scaling to 25% is to position the cursor between the letter and the ! and add 75 units of kerning. I've started from the idea that the theory says a normal space is equal to an en-space and changed the 25% method to a 50% method so it would equal a 1/4th of an em (50% of an en) and tested it against the 75 units of kerning. It gave the same visual result and scaled proportionally, so far so good. I like being able to paste my space somewhere else so I still prefer my method for now.
My other question is...I can't figure out how 75 units of kerning could equal 1/4th of an em... Isn't an em supposed to be split in 1000 units for kerning and so 75/1000 does not equal 1/4th or even 1/8th... What is the number used in the kerning field based on?
Now the teacher feels stupid... :-) Sorry about the long post. Any help in figuring this out is greatly appreciated!