Factual Opinion
A factual opinion is an opinion containing factual evidence, not only your own opinion. It's an opinion in which there's evidence to back it up, furthermore, the opinion shouldn't just contain bias ideas of your own, but in fact an opinion that anyone else can agree on.
For example, let's say you've created a piece of work. An opinion would sound like, "Personally, I don't like the fog around the picture"
A factual opinion would sound like "You shouldn't remove the fog around the picture because it looks a bit more realistic and adds vividness to the picture"
A factual opinion would sound like "You shouldn't remove the fog around the picture because it looks a bit more realistic and adds vividness to the picture"