As black (or white) is relative and is a perception, is there an experiment where black can flip to white just by changing the associated background image?
Yes, there is. Sort of. You can take a patch that is lighter than it's surround. Maybe it won't look white but it will look light grey. You then increase the lightness of the surround and when the surround gets really bright the original light grey patch will appear darker and darker and will eventually appear black. Of course, you can also go the other way.
![BRASIL vs. URUGUAY [1-1] | RESUMEN | ELIMINATORIAS SUDAMERICANAS | FECHA 12](http://i.ytimg.com/vi/-hWBAuxF1eY/mqdefault.jpg)
How do you define black?
As black (or white) is relative and is a perception, is there an experiment where black can flip to white just by changing the associated background image?
Yes, there is. Sort of. You can take a patch that is lighter than it's surround. Maybe it won't look white but it will look light grey. You then increase the lightness of the surround and when the surround gets really bright the original light grey patch will appear darker and darker and will eventually appear black. Of course, you can also go the other way.