## Correct spacing between letters

Hello everyone.

I've been wondering for a long time about kerning and wonder if anyone can help me out with this specific issue I have, I've tried to illustrate it as clearly as I can.

On the attached image I've tightened the whole word as an example without manually kerning anything. Usually if I wanted to keep it at this general tightness my first instinct would be to match the space between each letter to the space either side of the "o". However, I've always been slightly confused as to what should be correct spacing (in this example) for the letters circled.

A) I assume l's should have more space than anything else so I'd leave it as is.
B) The "s" and "t" are touching here, how much space would I put between those?
C) The "r" and "a" - nearly touching?
D) "t" and "i" are especially close. Should they be pulled apart?

As I said these are some examples, ideally I'd like to know the correct relationship between each letter, number etc. Does anyone have the names of books/websites that define these rules? Everytime I pick up a book on typography it seems to just mentioning fixing the word WAR. I know about the W and A issue but what about everything else? (The number 1 always seems to be quite a distance from other numbers, particularly in Avenir, the typeface I've used in this example).

Hope that's clear, any help is much appreciated!

Did my image attach correctly? I'll try again.

See my notes on the "tight but not touching" spacing style:
http://typophile.com/node/69306

In this display style, equalizing closest distances becomes more important than balancing areas of space.
Alternatively: it looks like the letters are objects which have been horizontally stacked against one another.

Thanks for that Nick, I had noticed your post previously. While your suggestion makes sense, looking at the Pepsi ad in your examples - specifically the word "that" I notice that the space between the "t" and "h" is closer than the space between the "h" and "a". So it doesn't seem as simple as the kerned word "Helvetica" suggests. Or is it?

I'm not sure what the explanation for that is.
There are certainly different interpretations of the Tight But Not Touching style.
As the technique is manual, or "eyeballing", it might just come down to how the typographer feels on the day.
I know I try and kern a font in a single session, getting into the zone.

Well I like to think I'm comfortable with kerning as I generally practice Tight But Not Touching. But then I visit logo crit sites like Brand New and there's all sorts of folk pointing out spacing between certain letters that I just wouldn't have spotted. Is that just designers being picky?