What is a good font type and size for subtitles on a video to be used on a portal?

A question asked, my answer.

Not all typefaces are crafted and designed to be used when setting captions, text, subheads, and display headlines. Even though current technology makes it possible to set any typeface at any size regardless of the intended use of the original font design. It is not appropriate and the novice, apprentice, junior designer doing so often has odd looking results.

Knowing the demographics of your intended audience in addition to understanding the design brief are imperative steps to take in selecting a type design that performs well in the medium you intend to use.

Without at least that basic audience and design brief knowledge or my understanding what background you have or lack in graphic design and typography all I can comfortably steer you towards is to look at “Display” type.

Display or headline typeface is type that can forgo the extreme legibility and readability needed for long blocks of text at small sizes in favor of a stronger voice, more elaborate and expressive shapes, and a more distinctive look. Good quality display type are designed with subtle detailing, elegant proportions, and increased stroke contrast to have enhanced visual appeal at sizes above 24 point.

In what ever medium utilized, type and typography are visual media that are very much affected by size. It is important to select appropriate typeface font for the intended size range. This problem is one graphic designers are trained to solve. Typographic expertise is one of the reasons you hire and forge a business relationship with a professional graphic designer.