If you've decided to get a 4K TV, you're probably faced with the challenge of finding good content that makes use of it. Unfortunately, not everything labelled as 4K is really full 4K. This site helps you tell the difference. For something to be as authentically 4K as possible, it should ideally be shot, edited and rendered at a 4K resolution. However, in some cases -- especially older films from before a time when 4K really existed -- this might not be the case. RealOrFake4K helps break down the difference for individual movies. The site will note how a movie was shot, what process was used in editing and how that translates to a real-world viewing experience for you.
In some cases, even having something that was less than ideal 4K will still be better than a standard HD format. The site notes when the 4K media you're watching is an improvement, even if it doesn't reach the highest bar.