Do we need kerning against the space character?

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Tim Ahrens
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Do we need kerning against the space character?

Post by Tim Ahrens »

So far, Kern On does not do any kerning against the space character. I know that some people do that, however. So, the question is:

Do you want KO to support/generate kerning against the space?

If so, what is the reasoning behind it? What is the (visual/geometrical) reason for it? What are the principles that guide you if you do it manually?

Looking forward to your answers!
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Jeremy
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Re: Do we need kerning against the space character?

Post by Jeremy »

I do look at this, but am aware of combinations such as 'W W' or 'f W'.
Sometimes I have swapped out the space with a space.wide, or space.narrow etc.

I tend to review as a basic in consideration of standards and the whole type. Any kerns are small though.

/H/H/H/space/H/H/H/space/O/O/O/space/O/O/O/H/H/O/O/H/H/period/space/H/H/H/period/space/O/O/O/period/space/H/H/period/space/A/H/period/space/J/H/period/space/M/H/period/space/S/H/period/space/T/H/period/space/U/H/period/space/V/H/period/space/W/H/period/space/X/H/period/space/Y/H/period/space/Z/H/H/H/O/O/H/H/comma/space/H/H/H/comma/space/O/O/O/comma/space/H/H/comma/space/A/H/comma/space/J/H/comma/space/M/H/comma/space/S/H/comma/space/T/H/comma/space/U/H/comma/space/V/H/comma/space/W/H/comma/space/X/H/comma/space/Y/H/comma/space/Z/H/n/n/n/space/n/n/n/space/o/o/o/space/o/o/o/n/n/o/o/n/n/period/space/n/n/n/period/space/o/o/o/period/space/n/n/period/space/a/n/period/space/f/n/period/space/j/n/period/space/s/n/period/space/t/n/period/space/u/n/period/space/v/n/period/space/w/n/period/space/x/n/period/space/y/n/period/space/z/n/n/n/o/o/n/n/comma/space/n/n/n/comma/space/o/o/o/comma/space/n/n/comma/space/a/n/comma/space/f/n/comma/space/j/n/comma/space/s/n/comma/space/t/n/comma/space/u/n/comma/space/v/n/comma/space/w/n/comma/space/x/n/comma/space/y/n/comma/space/z/n

If you add it to Kern On I would possibly have it as an option unless a string of 3 can be considered – i.e. the glyph before the space – '. W' is a larger hole than 'f W' or 'W W'
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Tim Ahrens
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Re: Do we need kerning against the space character?

Post by Tim Ahrens »

Thanks for sharing this!

So, it seems that here, the main reasoning for any kerning against space is triplets? I had this feeling, too, that we don’t need kerning against the space character out of purely pair-based reasons.

Your trick to simply use a contextual space.wide or space.narrow is really good! I had never thought about that. Much easier to implement than triplets, it can easily be controlled in an MM environment, and probably also requires much less data to go into the font.
Eben Sorkin
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Re: Do we need kerning against the space character?

Post by Eben Sorkin »

I like to have kerns to space for text faces because it allows me to get a more even grey in a paragraph than I could otherwise get. I aim to make the space itself appear more constant in brightness. In a really large optical size display face I might also want to because all the spacing becomes more sensitive. Space wide and space narrow seem like a great way to get some of this impact without the kerning data overhead. But I really would want to option to automate this with examples if possible.
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Tim Ahrens
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Re: Do we need kerning against the space character?

Post by Tim Ahrens »

Thanks for your contribution, Eben!
Do you use positive or negative kerning against the space, and for which characters?
Eben Sorkin
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Re: Do we need kerning against the space character?

Post by Eben Sorkin »

The letters where the word space tends to look brighter/bigger than a default those with big open white spaces. H H no and vs T T yes. The Latin glyphs that I sometimes like to kern with space in caps are : A T V W Y X both sides; Right side L C F P K G; Left side J. The suitability of the gyph to kerning with a word space is very dependant on the design. In lower case the values are smaller because the white space is less but I do also sometimes do right side: c f k t; both sides v w x y. Numbers can also benefit from this treatment. Again depending a lot of the design but these might include: 2 3 4 5 7. Symbols like The UK pound sterling are sometimes quite bright on the right side. The various dashes can feel a bit loose set next to a space. I like to make sure that the nonbreaking space and other spaces that are are part of the word space kerning group numberspace, emspace and enspace for example.
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Tim Ahrens
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Re: Do we need kerning against the space character?

Post by Tim Ahrens »

It seems we need to distinguish different cases of kerning that involves the space character:
  1. Pairs with space that need negative kerning, as the sidebearings of the glyph are always chosen with neigbouring glyphs in mind, which means the “close elements” have to be over-represented. For example, thinking of a typical sans, the sidebearings of the V are not chosen so that the average distance (i.e. at half the cap height) is the same as the H, but looser, as the close zone at the top is not fully compensated by the loose zone at the bottom. Against the space, however, perception works more in terms of average distance or white area, so we need this correction. Examples: [ T] and [F ].
  2. Pairs with space that need positive kerning. Possibly after the f, which is is a unique case in that it is usually spaced specifically to work against LC without ascenders and it is “too tight” from an abstract, i.e. average distance or white area point of view. Example: [f ].
  3. Triplets (with space in the middle) that need to be tightened, as the same principles as normal kerning seem to apply across the space (but maybe weaker?). Examples: [L T] and [. W].
  4. Triplets (with space in the middle) that need to be widened as they would be too tight otherwise. Examples: [W W] and [f W].
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Tim Ahrens
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Re: Do we need kerning against the space character?

Post by Tim Ahrens »

3. Should be the easiest to implement: Just take all kerning pairs, “insert” a space in the middle, possibly apply a taming factor < 1, and export as triplets. Maybe I will try this as an experiment. From a typographic (semantic?) point of view, this may not be a crucial as normal kerning, as the space is meant to separate things from each other, but the increased visual consistency might be beneficial.
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