What is a font? Your design is about 80% composed of text. It is critical for the designer to understand typography in order to choose the fonts that will complement the design.
What is a font: basics
It is important to understand the terms of font structure in order to separate one font from another and understand the properties of each of them. First, you should understand these terms: the ascender line, the descender line, the baseline, the line spacing (leading), and the line height (X-height).
Most people read texts on the web or on mobile devices. Five rules for good typography can be applied both in print and in digital interfaces. Good fonts make the reading experience enjoyable, encourage a person to read more and effortlessly, so the choice of font should be aimed at maximum convenience.
This is the new default font in iOS, replacing Helvetica Neue. You can download it here. This font was created for readability, so that the text is optimally legible. It is worth noting that this font was created by Apple. In that video the font is described in more detail.
Depending on the font size, iOS automatically adjusts the character spacing and switches between the Text and Display font options. If the font size is 20 pt or larger, SF UI Display is used, and if the font size is less than 10 pt, SF UI Text is used.
When creating a design for iOS, your font size must be at least 11 pts in order to be legible on iPhone, iPad and Apple Watch. This is the minimum size, and the ideal is between 15 and 19 pt.
When using a modern font like SF, Proxima Nova, or Museo, you will find that they have several styles: Thin, Ultralight, Medium, Semibold, Bold, Heavy, and Regular. The font size and style complement each other. It is useful to remember that at 11-19 pt it is worth using Regular, at 20-34 pt – Medium, and for 34 pt and more – Bold. Light and Ultralight can be used when the font size is very large so that the text can be read, however, remember that large headers in iOS 11 are usually written in bold.
Ideally, line spacing should be 120-145% of the font size. If it is smaller, the text will look squeezed and will be difficult to read. When the spacing is perfect, each line has its own space, and everything becomes easier to read.
Number of characters per line
People read text faster, which is more extended vertically than text, which has more characters in a line. If the line is too long, the person experiences a large cognitive load, as he or she has to focus on each word in the line. To maintain a smooth reading experience, ideally, the string should contain 45-90 characters.
Hierarchy and interactions must communicate through your font. Use large bold for headings, a gray Medium font of 14-15 pt for signatures. Use less transparency for text that doesn’t contain the most important information.
What is a font: antique and grotesque
A serif or non-serif font is a good choice: it all depends on the type of application. A serif font is commonly used in applications that contain a lot of text, such as medium, iBooks, Bloomberg, and The New York Times.
Sans serif fonts are used more often as they are more neutral and safe. You will see them in most applications on the App Store.
Fonts are usually expensive, but there are several resources where you can download great fonts that look good in any design.
Google Fonts has an excellent interface and a good selection of fonts for any style possible. You can download font files and put them in an Xcode project to use them.
Skyfonts for Mac is a great app that lets you sync all your text files with your computer. If you want to download all fonts from Google Fonts, you can do it with this repository Github Typekit
Typekit has an excellent collection of free and paid fonts that are part of the Adobe Creative Cloud subscription. Some great fonts from the collection are Proxima Nova and Museo.
This is a great service that gives you the opportunity to try fonts for 60 minutes before you purchase them. You can also rent fonts for a fraction of their price to use them for a certain time.
Fonts, of course, are not limited to iOS applications, and the principles should apply to all spaces in which a person needs to read text.
This guide will tell you more about font combinations, apostrophes, quotation marks, brackets, and so on.
A Five Minute Guide To Better Typography
A nice guide with animated snippets that talk about every aspect of typography in such a way that a smile remains on your face. I highly recommend it.
Gradually, you will want to create a hierarchy and contrast in the text using more than one font. This guide will be useful for selecting font pairs.
How the web became unreadable