Letter-fitting is planning and programming the characters layout. Provision that is then translated into sidebearings values, measure of how much space is around a single letter, and kerning values, measure of how much two letters should be relatively moved close or away from the base placement determined by sidebearings. So sidebearings and kerning are the first and second order letter-fitting values. This process should guarantee, as far as possible, harmony in composition, an effective sign recognition and an easy reading. These needs not always coincide and aren’t freely and independently reachable. A provision of letters aimed at facilitating their interpretation, legibility, would require a clear separation of the signs according to a non-collision criterion that could be called proximity. It’s no doubt important to understand what you read.
But it’s also important to read in a smooth, seamless, quick and easy way. A provision of letters that may guarantee this readability should have rhythm. Why? Rhythm can be considered as a regular sequence of reference points that marks the eye linear movement: these motifs are the white spaces between the letters. The movement in space is timed by visual beats. The rhythm creates order and, therefore, predictability in the spatial location. There are many different letter shapes, of course, and not all the combinations could simultaneously ensure the absolute perfect legibility and readability. Some letters approaching, touching and overlapping undermine legibility. But moving them away creates gaps decreasing the white space homogeneity and, consequently, the readability.
Letter-fitting is essentially search for a compromise. A search, however, that is subject to further constraints. In metal printing type era, for example, the uppercases spacing was sometimes much larger than the lowercases. It was a way, inherited today by the OpenType ‘cpsp’ feature (capital spacing), to minimize the inconsistencies bypassing the technical limitations.
But it can also happen that letter-fitting becomes function of the reading speed like in a signal system;
or the density of information like in a magazine page;
or the reading ease like in a book page.
The use of a typeface, meaning the context, becomes a design starting point not only for the signs but also for the white space. Even more when you think in terms of scale factor: a text is essentially read, a single isolated word, you want a logo, a title or the name of a subway station, is basically observed. At different scales the relative importance of the texture created by the white spaces changes for the exact same reason that a display typeface requires a higher level of contrast and detail. At large scale it becomes more important to reduce the gaps and focus on the texture; at the expense of rhythm and proximity.
Finding the appropriate balance between rhythm, texture and proximity is the essence of the choices letter-fitting requires. Choices which, incidentally, are necessary because each font can contain a single unique letter-fitting. There would be no reason why font standards couldn’t incorporate different fittings to be interpolated on the fly as needed; eventually tracking driven.
It ‘s interesting to note that in the evolution of alphabetic writing systems, the letterfitting has become a necessity when certain shapes have become standard, over time. But evolution also took different and opposite routes. There are shapes that evolved and genetically modified to remove the need for fitting coming to outlines intrinsically capable of generating a regular pattern.
Others chose intermediate paths.
The Latin characters as we know them are located at the end of this hypothetical distribution of outcomes in alphabetic forms evolution. They have become what they are because the ease of pattern recognition has been privileged over the ease of layout, imposing the acknowledgment of pure geometric forms: lines, triangles, simple curves (circles, ellipses).
Not only functionality prevailed, but also an exact form of beauty between different possible forms of beauty.
The latin sans serif style is the ultimate evolution in a minimalist sense of the alphabetic form where the purity of shapes requires the maximum compensation capacity from the white space. No more serifs here to help.
So if letters are literal, stylistic and graphic meaning vehicles, then the white space is the carrier wave of this signal of letters. As such, it hasn’t got its own life. It shouldn’t be noticed (and when it happens it’s a transmission trouble, an interference). Pre-exists in the blank page space and is raised, as a perturbation, by the presence of the signs. Having happened to deal with the mathematical modeling of this evanescent object having latin characters as reference environment has been a necessary condition for trying to reach the widest possible generalization.