Reading the first few chapters of the Sorcerer's Stone, I became very curious about the Hogwarts letter over these lines.
...and the address was written in emerald-green ink.
...held up the letter so [the Dursleys and Harry] could read the green ink address...
(both from Chapter 3, The Letters From No One)
- ...the yellowish envelope, addressed in emerald green...
(Chapter 4, The Keeper of Keys and Grounds of Hogwarts)
We can see that the address of the letter that Harry received was written in emerald-green ink, which is also his eye color. However, I couldn't find out whether the letter inside the envelope was also written in green. I wonder if we can infer from this that young wizards and witches get their Hogwarts letter written in the same color ink as their eye. For example, would Ron have gotten his letter written in blue ink? If they do, the question will be How. Oh, and how will odd-eyed people's letter be like, if their right and left eye's color is different?