Did you know that ... 12 percent of our dreams are in black and white?
Is this true?
It's difficult to tell. Dreams are very hard to analyse scientifically since they can't be objectively measured, only self-reported. Dreams are notoriously difficult to recall after waking, so it's almost impossible to tell for certain.
There are some self-report studies which do assert that some proportion of dreams are in black and white, but this pattern is not seen in dream reports in various historical sources, so a plausible explanation is that black-and-white dreaming is caused mainly by exposure to black-and-white film media throughout the early 20th century, and that the percentage of dreams that are in black-and-white are skewed toward older populations who grew up with black-and-white films (though I don't personally know of any hard data on this point)
See this article by Schwitzgebel, 2001, who recounts several primary sources to this effect: http://philsci-archive.pitt.edu/267/1/dreamb&w010430.pdf
Schwitzgebel, E. (2002). Why did we think we dreamed in black and white?. Studies in History and Philosophy of Science Part A, 33(4), 649-660. PDF