Straight Red Strips?

Here is an optical illusion created by Herman J. Verwaal from his deformation series

Herman points out the red strips appear to be deformed where they cross the fluorescent lights. I agree the red strips seem to narrow as they cross the lights. Even more fascinating to me is that the red strips seem darker where they cross the lights. Yes the red strips only seem darker.

The fact is that the red strips have a red green blue measurement of R:246, G:4, B:0. No matter where in the strip you measure the color is constant. I find this fascinating because the red in each strip, where it crosses the light, appears to darken.


Herman J. Verwaal
copyright 2012
used w/permission

The bottom line is that the red strips above are perfectly straight and the shade of red does not change at any point in this image.

Herman has an excellent collection of Pop Art, Paintings, and Optical illusions. He has given me permission to feature his pieces here. This is just one of many. His illusion art ranges from color perception to distorted illusions.

Thank You for sharing these excellent illusions Herman.

*** Herman J. Verwaal's Trick Art, Pop Art, and Fine Art are available for purchase.

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Disappearing Color Optical Illusion

I ran across an illusion that purported that if you stared at the center the colors in the image will be represented by shades of gray. The best I could do with that illusion was shades of red. I decided that it missed the mark, but I recalled the Disappearing Fluff optical illusion that did cause colors to vanish into a gray mist. Using the color scheme from that illusion I modified the original image (developed by Ed Minchau) until I succeeded in creating an optical illusion where the colors faded away and all that was left were shades of gray.



Vanishing Color
(c)2012 Walt Anthony

Stare at the center dot (for about 60 seconds from about 12 inches away) and shortly the various colors should blend into various shades of gray. Did this optical illusion work as well for you as it does for me? Let me know.

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Magical Illusion or Optical Illusion?

Here we have an apparently green liquid being poured into a clear glass with normal lighting, but in the glass we see red liquid splashing around. Is this a magic trick or is there and optical illusion at play here? Read what the artist says below.



Color Illusion I
Flickr Artist - Catherine Jamieson

The artist that created this image, Catherine said,

"Addicted I am, I tell you, to complementary colors. If you put water in a jug and add green and red food coloring (to the same water, in the same jug) and pour it from one receptacle to another the illusion (light and refraction) is that it is green turning into red. It's really red-green reacting to the light. Cool, huh?"

Aside from Flickr Catherine has an excellent photoblog and had a book released last year titled Create Your Own Photo Blog. On her site she states,

"I honestly do believe everyone with a camera should have their very own photo blog - this is my effort to see if I can help with that. "

Check out her site and say Hi.

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Color Contrast Optical Illusion

The below two cubes share some things in common. The creator of this optical illusion states the following.

"Despite the fundamental difference in the apparent colour of the 'blue' tiles on top of the left cube, and the 'yellow' tiles on the top of the right cube, all the tiles are in fact physically identical (grey in both cases)."

I'll take this one step further and let you know that the RGB value for all 11 squares mentioned is exactly the same R:136 G:136 B:136. The blue and yellow squares mentioned are the exact same color as the gray block to the right.

Dale Purves M.D.
R. Beau Lotto
(c)2012

But they are not the only tiles on these cubes that look different but are exactly the same. Can you spot the other tiles that look different but are actually the same exact color?



The truth is that the optical illusion for tiles numbered 1 are the result of color contrast and the optical illusion for tiles numbered 2 and 3 are the result of brightness contrast.

With that said you must have no doubts that what I'm stating as fact is true. What's that you say? You don't believe it? Ok, OK already, quiet down. I guess we will just have to take the steps needed to prove that I am correct.

Project: Proving all the 1, 2, or 3 tiles are respectively all the same color.

There are a few ways you can prove that the tiles are the same color.

Before we continue, right click on the top image and open it in a new window. Now you have an image to work with.

1) You can use a graphics program like Photoshop, Paint.Net, Gimp or the Colorzilla extension for Firefox browser.

My choice is Colorzilla w/Firefox. Using the eyedropper tool you can determine that the RGB values of the respective tiles are the same, for number 1 tiles the RGB value is R:136 G:136 B:136, number 2 tiles have a RGB value of R:182 G:159 B:14, and number 3 tiles have a RGB value of R:75 G:45 B:138.

Not good enough for you, heh? Still not ready to trust that the computer is correct or you don't have an eyedropper tool? Either way you can move on to step 2 or 3 below.

2) Cut out a cardboard mask.

By viewing patches of the squares without the surrounding context, you can remove the effect of the illusion. A piece of cardboard with holes created in the right spots will work as a mask for a computer screen or as a mask for a the printed illusion. Holding up this mask to the image on the screen or printed paper should be enough to convince you. But if you were like my daughter nothing but this next step would do.

3) Print the image and cut out the respective tiles.

WARNING: Do Not use any specialty scissors your mother or wife uses for any kind of crafts, IE. quilting or fabric scissors. Doing this can be hazardous to your short term happiness. When in doubt get permission to use the scissors first.

This is another way to isolate the patches from their surrounding context. Cut out each tile along the edges. Remove them. Hold them side by side. Overlap the cut out tiles. Yup they're the same color. No denying it now, is there?

Please note that I have heard that some printers have "enhancement" processing that increases the contrast of edges. This can cause the printed squares to have slightly different RGB values. I haven't run into one of these printers yet where the overlapped squares didn't look identical, but your mileage may vary.

4) Of course you could just go to the interactive demo that the creator has up on his site. He shows both the color contrast and brightness contrast illusions, plus a few more that will make you think twice about believing what you see.

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Watercolor Optical Illusion

This is an example of the watercolor effect. This effect was first demonstrated by Baingio Pinna in 1987.

Simply put The watercolor effect is perceived when a dark (e.g., purple) contour is flanked by a lighter chromatic contour (e.g., orange). Under these conditions, the lighter color will assimilate over the entire enclosed area.

What does that mean? Take a look at the below image. You see 9 distinct squares. The center of each square looks white but the outer area of each square has taken on a watercolor shade, pink, green, yellow, blue etc...


Tic-Tac-Toe Board
(c)Walt Anthony
Created from samples
provided by Akiyoshi Kitaoka

The truth is that aside from the squiggly lines the only color here is white. The outer ring and the inner square are pure white.

Prove It: You can prove this by using the eye dropper tool in either of the following free graphics programs Paint.Net or Gimp or you can use the eye dropper tool in the free Colorzilla extension for Firefox browser. When you use these tools you will find that RGB value of everywhere on this image that is not a squiggly line is R:255 G:255 B:255 or #FFFFFF.

Print out this image and slide it into a plastic document protector. Now use an earasable marker and you have a reusable optical illusion Tic-Tac-Toe board.

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Checker Shadow Optical Illusion

This is the Checker Shadow Optical Illusion. It was developed by Edward H. Adelson of the Perceptual Science Group at MIT. The interesting thing about the below optical illusion is that square A is the exact same shade of gray as square B.

One way to identify a color is by it's Red, Green, Blue values or RGB for short. When written for 24 bit truecolor R:0 G:0 B:0 is black and at the other end of the spectrum R:255 G:255 B:255 is white. The other 16 million or so colors fall somewhere in between. Squares A and B below each have the same RGB value of R:120 G:120 B:120.


So now that I said it is true you have all obviously accepted the fact that square A and square B are indeed the exact same shade of gray, right? I mean if it is on the internet it must be true. Would it be easier if you could prove it to yourself and any skeptics you might run into (like Mom and Dad or that annoying sibling). Continue on and we'll get around to proving my statements correct.

Project: Proving square "A" is the same shade of gray as square "B".

There are a few ways you can prove that the 2 squares are the same shade.

Before we continue, right click on the image and open it in a new window. Now you have a giant image to work with.

1) You can use a graphics program like Photoshop, Paint.Net, Gimp or the Colorzilla extension for Firefox browser.

My choice is Colorzilla w/Firefox. Using the eyedropper tool you can determine
that the RGB values of the grays in both square A and square B are 120-120-120.
Not good enough for you, heh? Still not ready to trust that the computer is correct or you don't have an eyedropper tool? Either way you can move on to step 2 or 3 below.

2) Cut out a cardboard mask.

By viewing patches of the squares without the surrounding context, you can remove the effect of the illusion. A piece of cardboard with two holes created in the right spots will work as a mask for a computer screen or as a mask for a the printed illusion. Holding up this mask to the image on the screen or printed paper should be enough to convince you. But if you were like my daughter nothing but this next step would do.


3) Print the image and cut out the squares.

This is another way to isolate the patches from their surrounding context. Cut out each square along the edges. Remove them. Hold them side by side. Overlap the cut out
squares. Yup they're the same shade of gray. No denying it now, is there?

Please note that I have heard that some printers have "enhancement" processing that increases the contrast of edges. This can cause the printed squares to have slightly different values of gray. I haven't run into one of these printers yet where the overlapped squares didn't look identical, but your mileage may vary.

WHY you ask? You might have come to terms with the fact that the two squares are the same shade of gray, but how does this optical illusion work? The creator of the illusion has an explanation here.

READ MORE - Checker Shadow Optical Illusion

American Flag Optical Illusion

I was wandering around the web looking for a way to share this site with more people and came across the American Flag League. This is a blog alliance that the only requirement to get on the list is to have an American Flag on your site. So I thought it would be a good time for this optical Illusion.

This is the first after image optical illusion that I have placed on this blog so here are some instructions. Stare at the red dot in the center of the flag image for 30-60 seconds then look at the center of the white spot below or any white surface in the area.

Why did you see a red, white and blue American flag? Those colors are the negative of the above black, blue and yellow image. The negative is what is left after you stop staring at the image. If you were to take the above image and open it in MS Photo Editor and select negative from the effects menu you would have a nice bright American flag.

Here is the current list of American Flag League members.

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Pacman Optical Illusion

This is an amazing optical illusion.

I found this illusion on several sites on the internet. One semi-popular link farm spent 6 pages of comments discussing this optical illusion. Many were confused about what this optical illusion was all about so let's start off with the following. (If all goes well you might see something like the small image to the right).

1. The below image is an animated gif file.
2. The image is composed of 12 frames, each frame has 11 purple dots on a gray background.
3. These frames are designed so it looks as if one dot is removed at a time progressing clockwise.
4. There is no green dot in this image at all.
5. There is no green dot in this image at all.
6. There is no green dot in this image at all.
   

Stare at the center cross, you will notice a green dot start going around the circle. As you continue to stare the green dot will appear to consume the purple dots until all that is left is the green dot circling the cross, then the purple dots will reappear one by one until they are all visible again.

Jeremy L Hinton
Copyright 2004
Used w/permission

Simply put the reason you see the green dot is because that is the afterimage (or negative) of magenta.

For a more thorough explanation of how this optical illusion works go here.

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Simultaneous Contrast Illusion

Viewing two colors at the same time influences both of their appearances. The following is an example of simultaneous contrast.

It is easy for me to state that the gray bar is exactly the same shade of gray throughout it's range. Most of us however will swear that the bar varies in color as it progresses across the page. If you have access to a color identifier program you will find that the bar is color 7e7e7e at every point within it's border. Otherwise put the RGB value is R126 G126 B126.


Simultaneous Contrast Illusion.
The gray bar is the same shade throughout.

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Color-constancy illusion

I have seen this illusion many times and for some reason never focused on it. I must have past by this optical illusion a dozen times before finally focusing on an article and reading what it is about. It is very similar to the checkershadow illusion but involves color rather than just shades of gray.


Image Copyright Dale Purves, R. Beau Lotto and Surajit Nundy.

The "blue" tiles on top of the left cube and the "yellow" tiles on top of the right cube are actually the same shade of gray. If you use an eye dropper tool to fine the red, green, blue values of each square you will find the value is not precise across any square but they are all definitely grey with a RGB value around R142 G149 B157.

Another interesting tidbit is that the red tiles on top of the left cube are orange and the red tiles on the top of the right cube are purple.

To read more about this illusion read either of these articles: American Scientist: Why We See What We Do and Discover Magazine: Sensory Reflexes.

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Cow and Fly Optical Illusion

I also found this optical illusion at Archimedes-Lab. This is one of the better illusions that require you to stare. The clarity of the picture after you follow the instructions below is amazing. Try it.

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The Haze Illusion

From the same team at MIT that brought you the Checker shadow illusion here is a flash movie demonstration that outlines how the some shades of color can be made to look different when the context of what it around them changes.

READ MORE - The Haze Illusion

Boston University Brings You Project LITE

This is an excellent interactive site that explores color, light, motion, depth, form and other interesting visual phenomena.

Of particular interest on this site is their LITE Vision area. This area includes a range of visual effects and illusions. Currently under development, it is written in Flash. Many of the applets allow the user to explore, manipulate and enhance the phenomena under study.

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Checker Shadow Optical Illusion

Lesson number one on this blog "Seeing isn't Always Believing."

Let's start by stating the not so obvious. Square A and Square B below are the exact same color. Hard to believe isn't it?

I look at this and find it hard to believe. But I used the extension in Firefox called colorzilla which provides you with an eyedropper tool. I checked both of squares and sure enough the RGB values of the grays in both square A and square B are 120-120-120.

That wasn't good enough for my 11 year old daughter she printed the picture out, cut out the squares and put them next to each other an sure enough they were the same exact shade of gray.

Click on the picture for a larger image.

The squares marked A and B are the same shade of gray.

Proof Explanation Download images More illusions

©1995, Edward H. Adelson. These checkershadow images may be reproduced and distributed freely.

This very moment I know they are the same color, but my eyes refuse to allow me to see it by just looking at the picture. Try and convince yourself that they are the same color. I know it is true but I don't see it as being true.

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