The movie adaptation of Fifty Shades Darker is scheduled to hit theaters on Feb. 10, continuing the risque storyline of the bestselling novel Fifty Shades of Grey series. Which got us wondering: Is it actually possible for a person to distinguish that many shades of such a neutral color?
There is no definitive answer. The scientific literature reports a wide range of values for how many shades humans can see, while computers can display up to 256, depending on the program. So to explore this question, TIME put together a simple quiz to test how many shades of gray--yes, that's the American spelling--you can distinguish. You'll be presented with eight slides of nine shades each, some of which are different from the background color and some which are not. Note that not every slide has the same number of alternate shades.
It should be noted that this quiz is not scientific. Most research-backed color tests are designed to test for types of color blindness and avail themselves of colors other than gray.