Analysis of information sources in references of the Wikipedia article "Blackboard bold" in English language version.
Inline: A letter in which the inner portions of the main strokes have been carved away, leaving the edges more or less intact. Inline faces lighten the color while preserving the shapes and proportions of the original face.Hutchings, R.S. (1965). "Inlines and Outlines". A Manual of Decorated Typefaces. Hastings House. pp. 10–11.
Consuegra, David (2004). American Type: Design & Designers. Allworth Press. "Handtooled typefaces", p. 280; "Inline typefaces", p. 282; "Open face typefaces", p. 286–287.
The sign for bold type is a wavy line beneath the words or symbols in question; for security the word 'bold' may be added in the margin.
The [1985] blackboard bold letters [...] are blocky in appearance, somewhat similar to those in the Monotype blackboard bold, but of much lower quality. (It's no surprise that Knuth did not like them.)
The [1985] blackboard bold letters [...] are blocky in appearance, somewhat similar to those in the Monotype blackboard bold, but of much lower quality. (It's no surprise that Knuth did not like them.)
The [1985] blackboard bold letters [...] are blocky in appearance, somewhat similar to those in the Monotype blackboard bold, but of much lower quality. (It's no surprise that Knuth did not like them.)
Design choices of Blackboard Bold alphabets again fall into multiple groups. One group favors a serif design which is derived from the main serif font: [...] Another group favor a sans-serif design which may be unrelated to the main sans-serif font: [...] Finally, the designs of individual letters can vary significantly among different math fonts, and are an additional consideration in font choice. For example, some users may have fairly strong preferences regarding such details as to whether the stem or the diagonal of the letter 'N' is double-struck.
Note: Characters highlighted [in yellow] are in the Plane 0 [Basic Multilingual Plane], not in the Mathematical Alphanumeric Symbols block in Plane 1.