don't adjust your screens we're doing an optical illusion where if it works you're going to see
color on your side of the screen even though you're looking at a black and white video
now right now you're looking at a negative image and if you really want this experiment to work
well just make sure the brightness is all the way up on your screen and the screen is moved as close
as you can to your face the more we can take over your field of vision the better this is going to
work so i need you to keep focusing right here and in a matter of moments i'm about to switch this
to a black and white video and yet momentarily you will still see color like right now
pretty crazy right welcome to impossible science today we're going to transform a black and white
image into one's full of color now it sounds impossible and in fact this has been an idea
for magic tricks for countless years as we try to find ways to make color appear
at our fingertips and whether it's done with a deck of cards or a magic coloring book doesn't
matter because the real secret behind making color appear turns out this one is possible through
science if we want to trick the eye we should know how it works if we take a closer look at
the back of the eye there's a thin tissue known as the retina now the retina is comprised of two
different types of photoreceptive cells there are rods and there's cones the rods are responsible
for detecting different levels of light and are also responsible for revision at nighttime while
the cones they're responsible for detecting the colors the red the greens and blues in different
combinations both the rods and the cones work together to send signals down the optical nerve
and up to the brain where the brain deciphers those signals to see what we're looking at
now that we understand the pipeline well let's figure out how we can trick it
okay we're going to trick the eye by using what's called an after image an after image is what
happens when you engage the same photoreceptors the back of the eye for an extended period of time
roughly 20-30 seconds now what you don't notice throughout the day is that your photoreceptors
in your eye are constantly being adjusted see you're constantly focusing on different things
you're looking at different bright lights and different color shades and those photoreceptors
are adjusting now don't think there's only like a few of these things there's about 90 to 120
million rods in your eye and there's roughly six or seven million cones in your eyes so you can see
there will already be a lot of different adjustments going on throughout the day but
what we want to do is tire the same photoreceptors out for an extended period of time so let's do the
experiment again and i'll walk you through what's happening so here we go i need you to focus right
here and i'm going to stay as still as possible as i explain what's happening so that i can engage
the same photoreceptors what's happening right now is the photoreceptors in your eyes the ones
that are seeing the bright lights are telling the brain that it's seeing bright lights bright colors
while there's other photoreceptors that are detecting the darker shades and the darker colors
now they're not working as hard as the ones that are detecting the bright lights the ones that
are detecting the bright lights are getting tired and about 20 30 seconds of this they're actually
sending a weaker and weaker signal to the brain the brain is starting to realize this is the new
normal when we switch to black and white well the photoreceptors that were not engaged as much the
first time are now coming at full strength and this is very overwhelming to the brain
the brain instantly thinks it's looking at the negative so let's give it a shot and if you blink
you momentarily see color in fact you can actually look at a white wall and you should still be able
to see color that's the after image pretty crazy when you think about it see you can even put this
into test you can actually just look at a color wheel and you can see how our logo even was in the
background was changing colors anything that was white the inverse was black just as much as those
red greens and blues that the cones were detecting the cyan in our logo looked like red just as much
as green looked like magenta and you can actually see a color wheel in action which i think is
pretty cool now if you enjoyed making a black and white image look like it has color let me know in
the comments below let me know if you saw magic in action or you saw science in action and if you
enjoyed the video make sure you let me know by clicking the like button and sharing the video
with your friends until next time stay curious because the right question changes everything