In class we did a few activities where we looked at a dot in the middle of an image and theoretically were supposed to see an after image. As I was scrolling through Facebook one day, I saw this video, which I attached below. In the video, the subject begins by staring at a blue dot in the middle of a false color image for about 20-30 seconds before looking at the same photo but in black and white. Once you adapt to the false color image and the black and white photo is presented, the photo comes out in color. The video briefly explains that it is due to adaptation of light sensitivity of the receptors in the eyes, mostly the cones due to the fact that they are responsible for color vision.

https://www.youtube.com/watch?v=3P8q_dCU3RI#action=share