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On NASA's recommendation, I'm at loss here > When specifying font height, or accessing graphs to determine the size of a lower-case character, the distinction
by unexistance 10y ago
On NASA's recommendation, I'm at loss here
> When specifying font height, or accessing graphs to determine the size of a lower-case character, the distinction between “x” height and overall size should be made.
> As a general recommendation, the “x” height of a font used for important flight-deck documentation should not be below 0.10 inch.
> The recommended height-to-width ratio of a font that is viewed in front of the observer is 5:3.
> The vertical spacing between lines should not be smaller than 25–33% of the overall size of the font.
> The horizontal spacing between characters should be 25% of the overall size and not less than one stroke width.
- phlo 10y agoThose seem like very reasonable points. Are you confused by the terminology? If so: - "x" height refers to the height of the mean line of lowercase letters, e.g. the lowercase letter "x". Ascenders (on letters like l, t, k) will exceed this height. - height-to-width: seems straightforward: wider fonts may often look more modern (see e.g. the Eurostile vs. Frutiger comparison in the article), but are harder to read. - spacing: allow for enough whitespace vertically and horizontally. This, again, improves legibility compared to condensed fonts.
- michaelbuddy 10y agoThis all checks out to me. They are talking about flight deck documentation, which means, the guidebook type can be small but not too small to read due to movement and perhaps if the reader is in an emotional state. You can imagine reading instructions on Apollo 13 after the increase in Carbon Dioxide just to go through a power down sequence checklist. Floating around, emotional state, perhaps some brain dysfunction due to air composition and lack of sleep. You don't want the type too small.