A file cannot be 'Unicode'. Unicode is just a catalog of symbols one might want to express in writing. An encoding (like ASCII or UTF-8) describes how bytes ar

A file cannot be 'Unicode'. Unicode is just a catalog of symbols one might want to express in writing. An encoding (like ASCII or UTF-8) describes how bytes are mapped to such symbols. ASCII only describes 128 characters whereas UTF-8 can represent any Unicode symbol in bytes. Notably though, UTF-8 is a strict superset of ASCII. That is, every character ASCII represents is represented by the same bytes in UTF-8. So encoding Romeo and Juliet in ASCII or UTF-8 results in the same exact file.