I'm a Turk. Growing up I've always considered us Turks to be White. On application forms I've always identified as such and I know many fellow Turks do. It's not hard to see why if you are familiar with Turkey, we're a mostly light skinned people of various tones (light eyes and light hair is normal to see) but with some darker individuals as well. In looks and diversity we are not too different from our neighbours the Greeks and other European Mediterranean.
What is the historical basis for Turks being seen as a dark people? I notice it a lot. For instance I've shown friends of varying ethnicities pictures of my family and celebrity Turks, and they're often shocked at the number of Turks that "look white". To me they look Turkish. I guess the fact that I'm personally olive skinned with dark curly hair throws them off as well, they probably assume other Turks look like I do (my Sister on the other hand is white, straight light brown hair, gray eyes, she says people are shocked when she tells them she's Muslim).
Another anecdote is when a blonde cousin of mine went on a school trip to Poland. She said people would often stare at her walking around with her schoolmates, presumably because they thought she was Polish. And yet another is an Uncle who used to be a sailor on trade ships. He says that when they went to South Africa during the Apartheid era that he and his crewmen were treated as Whites.
But even looking at historical depictions of Turks we're thrown in with Moors, Saracens and pictorially representations have usually made us look like people from the Middle East in our looks, and I don't mean clothing which I am aware was similar to our Muslim neighbours. But this is not how I (and other Turks) self-identify us to be and looking at us it's clear as well.
I'm well aware that the original Turks from Central Asia were likely similar in looks to East Asians, so I don't want any answers pointing that out.
My own guesses to this question is that our Muslim identity trumps our looks. In other words most Muslims in the world are not similar to Europeans in looks, so us Turks are just stereotyped along for the ride. Another theory I have is that the large number of Turkish Kurds (who are on average darker and less white looking than ethnic Turks) distorts the issue as well.
What is the expert historian's answer?
I'm leaving this thread up for a little bit, but please note that our subreddit deals with history, and all answers discussing current racial classifications will be deleted. To anyone considering posting a reply: please restrict yourself to historical perspectives on the Turkish people only.