It's really great information about passport colors. I was wondering reasons behind it as well. I have Turkish passport but we have few different colors for passports. Red one is ordinary passport which they give to people mostly. But if a person worked for state as officer or teacher etc. they will get green passport and it's visa free to lots of countries, especially Europe is visa free for them (not counting Brexit). We have gray passport as well, it's service passport. I have green one, but soon I will get red one instead. My parents worked for state and their family has a right to get green passport until 25 years old. That's how it works in here.
I want to share this educative and interesting post on my next curation post if you give me permission. You can find details on my post. I shared my first curation post for only Vietnamese community. I want to add this one to my next post. If you want to get featured please let me know today, because I will share it at Friday night in Vietnamese time. Keep posting great posts!