Adobe PS: dieresistonos
Unicode: 0385
Script: Greek
Dialytika-Tonos
History and examples of use
A combination of Greek accents dialytika and tonos, applied to the second vowel in a sequence that would otherwise be pronounced as a diphthong to indicate that the vowel is both pronounced separately (dialytika) and stressed (tonos).
Design
The dots of the dialytika in this combination may be slightly smaller and lighter than in the normal dialytika. Likewise, the tonos may be narrower and slightly steeper than the normal tonos mark in order to better fit between the dots.
Be aware that this diacritic frequently causes spacing problems with adjacent ascending letters, especially lambda.
Casing
When Greek text is set in all-caps or small-caps, tonos and other accent marks are conventionally removed. When this rule is applied to the dialytika-tonos, the tonos mark is dropped, but the dialytika remains, e.g. μαΐστρος -> ΜΑΪΣΤΡΟΣ.
Since there is no corresponding uppercase character for ΐ or ΰ, software should correctly case map these to Ϊ and Ϋ. Casing of Greek accents for small-caps can be handled contextually in OpenType fonts using the <calt> feature.