
Optical illusions that show how color can trick the eye - octoploid
http://www.washingtonpost.com/blogs/wonkblog/wp/2015/02/27/12-fascinating-optical-illusions-show-how-color-can-trick-the-eye/
======
jader201
I never joined the discussion about the dress (I was actually removed from
technology pretty much until after the whole debate died down, after which I
experienced another interesting phenomenon).

But what is fascinating to me is that the day following the debate, I saw the
image in Wired [1] and for the life of me could not possibly see black and
blue no matter how hard I tried.

I just now read this article, looked at the image at the bottom, then tried to
find the original Wired image, and now cannot see white and gold. The
influence is so strong that part of me almost thinks it's not the same image.

It sort of reminds me of when I first figured out how to "see" those
stereograms, and how once you know how to see one of them, seeing any of them
is easy.

[1] [http://www.wired.com/2015/02/science-one-agrees-color-
dress/](http://www.wired.com/2015/02/science-one-agrees-color-dress/)

~~~
ars
I had the same effect. One day I see gold and no matter how I try I can not
make it black.

The next day, with the exact same image and background, the parts that were
gold are now solid black, and I can not understand how they can possibly be
gold.

I can understand how different eyes might see it differently, but how my own
vision changed, and so completely, I don't understand.

It's like these images that trick a neural network:
[http://www.wired.com/2015/01/simple-pictures-state-art-ai-
st...](http://www.wired.com/2015/01/simple-pictures-state-art-ai-still-cant-
recognize/)

------
pavel_lishin
These discussions always remind me of David Langford's work:

[http://www.infinityplus.co.uk/stories/blit.htm](http://www.infinityplus.co.uk/stories/blit.htm)

[http://www.lightspeedmagazine.com/fiction/different-kinds-
of...](http://www.lightspeedmagazine.com/fiction/different-kinds-of-darkness/)

[http://ansible.uk/writing/c-b-faq.html](http://ansible.uk/writing/c-b-
faq.html)

~~~
DanBC
I loved Blit! I used to subscribe to Interzone when Blit was published. Those
Interzone anthologies were excellent. Whoever owns the rights should sell them
as ebooks if they don't already. (EDIT: this is I think the third mention of
Blit on HN)

~~~
pavel_lishin
I think I might end up having to just buy Langford's "Other Kinds of Darkness"
somewhere; none of my local libraries have it available for checkout.

------
georgemcbay
This has been covered on HN before (IIRC that's where I first read about it),
but my favorite vision color "trick" is the McCollough Effect, mostly because
of how long it lasts (weeks in my case, YMMV):

[http://www.cheswick.com/ches/projects/me/](http://www.cheswick.com/ches/projects/me/)

------
niccl
I know it's slightly off topic but I've been fascinated with the idea of blind
people having 'optical' illusions. Eg does the cafe wall illusion
([http://en.wikipedia.org/wiki/Café_wall_illusion](http://en.wikipedia.org/wiki/Café_wall_illusion))
work if you're blind and investigating a real cafe wall with that pattern
using your fingers? Or are there other things that _do_ create perceptual
illusions because of the different way blind people experience the world?

~~~
ars
The illusions mostly happen in the eye, not in the brain. So I don't think
they will work for touch.

The eye does not transmit "dots" of color to the brain, but rather processes
images very much.

Some of the "layers" that are transmitted are edge, motion, and color. So
motion illusions happen in the eye.

------
rasz_pl
[http://xkcd.com/1492/](http://xkcd.com/1492/)

I suspect people seeing white/gold live/grew up in sunny climate with blue
sky, sea?, maybe blue walls/wallpaper in their bedroom. Basically people
primed for seeing things illuminated by blue tinted light.

------
JohnHammersley
If anyone's interested in recreating some of these, LaTeX provides a neat way
to do so:
[https://www.overleaf.com/gallery/tagged/illusions](https://www.overleaf.com/gallery/tagged/illusions)

------
figseed
So the popular hypothesis is that the dress is black and blue.

I have now seen so many different sites and authors try to explain the
phenomenon, all based on the "proof" that some random woman named Caitlin
McNeil who first offered the disputed picture originally claiming she saw it
as white and gold in the picture, saw it some days later in person, said it
was definitely black and blue and offered a picture of an indisputably black
and blue dress that appeared to be identical or at least too similar to be
able to tell a difference definitely.

The issue to me is that I'm seeing sites like Wired and I f __king love
science explain how the dispute is possible based on optical illusions and
ultimately say that the dress is black and blue because of the other image and
the claims of a dress manufacturer with no credence to possibility that the
dress in one picture may be different than the dress in the others and that
dressgate might just be an elaborate hoax.

The thing is, you can just as easily explain why the dress is white and gold
and appears blue and black to some people given the intense back lighting in
the disputed image implying sunlight in the background and the effects of
reflected UV light can play on shaded white objects (think black uv lights) or
effects like solarization that can happen in digital imagery.

The thing is, I'm sick of hearing the dress is blue and black because
"science", when science hasn't been involved in anyone's "proof" of the
effect. What you have is a hypothesis. Want to make it a viable theory? Take
the black and blue dress or one of the identical ones from the designer
claiming that's their black and blue dress and recreate an identical image
that appears white and gold with the same tonal qualities and environmental
lighting. Until someone does that, I don't think there's any reason to
continue "proving" why the dispute exists with non-science or arguing about
this nonsensical bullshieza as it has become a gargantuan distraction from
reality whether or not it was originally meant to be.

~~~
vacri
The main article describes differences in perception of colours due to
surrounding colours. It's a well-researched topic in science. I learned stuff
like this in my neurophysiology degree over 20 years ago.

Dismissing it as "'because science'" and demanding that there be an
invalidated null hypothesis before you can draw on scientific knowledge is
just being wilfully obstructive. Do you really re-do all your basic
experiments before you conduct the one that rests on them?

~~~
figseed
Well the main article shows a bunch of demonstrations of how objects can
appear lighter than they are when contrasted against a dark background which
makes logical sense.

In the disputed image however, you have a bright background (so bright in fact
that it causes glare on the lens over the right shoulder of the dress)
supposedly making the dress appear lighter than it is. If anything I would say
that the optical illusions offer evidence of why the dress would generally
appear darker than it actually is than why it would appear lighter.

My problem with the "because science" isn't meant to be dismissive or imply
that the principles that are argued aren't valid or plausible, my problem with
"because science" is that a lot of the articles and videos made to describe
the phenomena are titled something to the tune of "Science explains why people
see different colors" and offer one of a varied set of plausible hypotheses,
but they are explaining something without any controls.

I see it like being told you have cancer, asking the doctor "why?" and her
saying "have you ever smoked cigarettes?" you saying yes, and her saying,
"Well it's widely known and has been repeatedly proven that cigarettes are
carcinogenic, there's your explanation."

In the same light, to me, saying the dress is interpreted differently because
our brain plays tricks on us such as in optical illusions (which I don't
refute at all) and that's why people are seeing it as different colors is
completely unscientific to me because it doesn't have controls for things such
as the type of screen people are viewing things from (glass vs matte), the
color temperature of the screen (anyone running f.lux?), the viewing angle,
auto-dimming screens based on ambient light, the effects of anti-glare
material in some screens all of which may contribute to why not only different
people see the image differently, but why the same people see the image
differently based on different times/environments.

And given the amount of time and energy people have devoted to discussing
this, I don't see why asking for evidence of one globally debated outlier
example is comparable to redoing experiments that have been widely reproduced.

The thing is, I don't have a problem with people using previously proven
concepts to expose potential explanations, I have a problem with people saying
that one hypothesis "scientifically explains" a phenomena because it's a
scientifically viable hypothesis.

\--- On a side note, thanks for disagreeing with me via a reply instead of
just arbitrarily down voting me because you don't like my opinion. I wish more
people on here shared the views you expressed on your about blob.

------
ZenoArrow
Okay, I'm probably going to get marked down for this, but... with that whole
"the dress" thing, am I wrong to think it's not just Photoshop and/or the
dress coming out different colours in the image depending on the light?

Take this example...
[http://assets-s3.usmagazine.com/uploads/assets/articles/8371...](http://assets-s3.usmagazine.com/uploads/assets/articles/83714-the-
dress-sales-are-up-retailer-looking-into-white-and-gold-
version/1425052031_the-dress-retail-467.jpg)

Now does everyone seeing that see bronze and light blue on the left, and dark
blue and black on the right?

Supposedly these are images of the same dress. If anyone suggests they're
seeing the colours differently on this example, I'll be genuinely surprised,
but at the moment I find that unlikely.

EDIT: ...and the downvotes have started. How predictable.

~~~
ronilan
"the dress" is different.

In the "classic illusions" everyone (or at least the vast majority) of people
will describe what they are seeing in a similar manner (an "illusion").

Then, when given an "aid" (such as hiding part of the background) they will
"flip" and describe what they are seeing in a different manner ("reality").
There is no such "aid" for the dress (or at least I haven't seen such).

It is thus not an "illusion". It is a segmented perception of reality, where
reality is this one specific image discussed.

It demonstrates that given a specific set of colors on which there is no
argument (see wired RGB image), a composition of those same colors can still
be perceived differently, but consistently, by segments of the population.
They see a different "truth".

BTW my 10 people sample had 5 blue eyed people in the black/blue camp and 5
green eyed people in the white/gold camp.

~~~
rasz_pl
you want aid? open that image in a program with color picker and look at ze
pixels

