Felix Titling is, as its name suggests, a typeface strictly for titles, not for text. The fine details of its letters only become apparent at very large sizes. While its default space between letters is tight, it may benefit from being spaced out a bit for easier reading, especially if it’s going to be seen at an angle rather than straight on.
Felix Titling was originally created in 1934 by the Monotype Drawing Office as a metal typeface, with nothing but capitals, numerals, and punctuation. It has classic proportions, based on letters developed in the Renaissance by Veronese calligrapher and painter Felice Feliciano; he in turn based his lettering on ancient Roman inscriptions. The letters look like they were drawn based on geometry rather than handwriting. It has serifs, but they are tiny. Even the thick strokes in Felix Titling are relatively thin, and the thin strokes are very thin indeed, so its effect is light but elegant.