Cut the knot: learn to enjoy mathematics
A math books store at a unique math study site. Learn to enjoy mathematics.
Google
Web CTK
Best sites for teachers
Sites for teachers
Sites for parents
Terms of use
Awards

Interactive Activities
CTK Exchange
CTK Insights - a blog

Games & Puzzles
What Is What
Arithmetic/Algebra
Geometry
Probability
Outline Mathematics
Make an Identity
Book Reviews
Eye Opener
Analog Gadgets
Inventor's Paradox
Did you know?...
Proofs
Math as Language
Things Impossible
Visual Illusions
My Logo
Math Poll
Cut The Knot!
MSET99 Talk
Other Math sites
Front Page
Movie shortcuts
Personal info
Reciprocal links
Privacy Policy

Guest book
News sites

Recommend this site

Best sites for teachers
Sites for teachers
Sites for parents

Education & Parenting

Manifesto: what CTK is about Search CTK Buying a book is a commitment to learning Table of content Things you can find on CTK Chronology of updates Email to Cut The Knot Recommend this page

Simultaneous Contrast Illusion


This applet requires Sun's Java VM 2 which your browser may perceive as a popup. Which it is not. If you want to see the applet work, visit Sun's website at http://www.java.com/en/download/index.jsp, download and install Java VM and enjoy the applet.


Buy this applet

A few words.

Copyright © 1996-2008 Alexander Bogomolny

 

 

 

 

 

 

 

 

 

Whether consisting of one or two bars, the middle shape is painted uniformly throughout. However its perception is affected by the gradient scale distribution of the color in the background. The illusion is noticeable even for small ranges of the background gray and almost independently of the relative shape of the bar(s).

The bar could be made to fill the entire drawing area. Even then, in a brightness aftereffect, it seems to be gradient filled, at least for a few seconds. The impression disappears on close inspection.

There is another Simultaneous Contrast Illusion.

References

  1. A. Seckel, The Art of Optical Illusions, Carlton Books, 2002, #125

Copyright © 1996-2008 Alexander Bogomolny

28677905Page copy protected against web site content infringement by Copyscape


Search:
Keywords:


Latest on CTK Exchange
Math
Posted by Laura
2 messages
06:56 AM, Apr-15-08

Divisibility rules - Jargon buste ...
Posted by Carolyn
2 messages
08:35 AM, Apr-04-08

product of fractions
Posted by ke_45
3 messages
08:37 AM, May-06-08

Distance to the horizon
Posted by Monty
3 messages
04:38 PM, May-08-08

Mistake on the page (an aside, Be ...
Posted by Max
4 messages
10:28 AM, Feb-28-08

Nim Games - a query
Posted by Akash Kumar
1 messages
08:53 AM, Apr-15-08

A typo in
Posted by alexwajn
1 messages
11:36 PM, Apr-19-08