VOLT is a free tool available from www.microsoft.com/typography. It is mainly designed to add OpenType features to a font but can also be used to add characters in the supplementary planes, which some font editors cannot yet do. This article focuses on adding the characters beyond the BMP. Unfortunately, VOLT is not available for any platform other than Windows.

Important background information: VOLT uses glyph IDs as the basis for all its operations. A glyph ID is simply a number that tells where in the font the character is found (first, tenth, fifti- eth, whatever). It has nothing to do with a character’s Unicode value or any other meaningful characteristic; it just uniquely identifies each glyph in the font. Such glyph IDs are a part of any TrueType font and are created for you by your font editor. VOLT also stores information in special additional tables that are not part of a standard TT font; these tables allow you to save the font, test it, and return to edit your work. These tables are removed as the last step in creating a finished font.

If you are using FontLab, you need to understand under what circumstances glyph IDs are changed. FL provides many different ways to display the characters in a font: by Unicode value, by name, by glyph ID, etc. You can switch the display around as much as you like; the position of a character in the actual font database (and therefore the glyph ID) is not altered unless you do one of two things. 1) While in glyph index mode (entered by clicking on the little black 1-2-3 icon on the FL toolbar), you highlight one or more characters and drag them to a new position. 2) You right-click on a character and choose Sort…

Download pdf Microsoft Volt to Adding Supplementary Plane Characters to a Font