		COLOR PHENOMENA				Page: 11. 03
Introduction	Ingredients	Spectra	Attributes	The Human Eye	Color Mixing	General Terms
Color Spaces	How to measure	Color Scales	Color Effects	After Images		Contents

	Color Effects
	COLOR CONSTANCY on page 11.00
	COLOR METAMERISM on page 11.01
	SUCCESSIVE CONTRAST on page 11.02
	SIMULTANEOUS CONTRAST and VISUAL ILLUSION on this page

SIMULTANEOUS CONTRAST and VISUAL ILLUSION

CONSTANT UNDER CONSTRUCTION

Simultaneous Contrast refers to the visual influence of a color in close proximity to another when the two are viewed at the same time. The color in the greater quantity influences the other to chance in some way. This may be a hue, value, or chroma change or a combination of characteristics.

Simultaneous Contrast is a perceptual effect in which color appear brighter and smaller against a dark background than against a light background.

Simultaneous Contrast is the effect created by two complementary colors seen in juxtaposition. Each color seems more intense in this context.

Simultaneous Contrast is a partitive color reaction when color is in a complementary setting.

Simultaneous Contrast is the phenomenon in which the perceived color of an area of a scene tends to take on a hue opposite to that of the surrounding area. Thus a grey square on a red background will take on a greenish tint.

Simultaneous Contrast is when two colors, side by side, interact with one another and change our perception accordingly. Since we rarely see colors in isolation, "Simultaneous Contrast" affects our sense of the color that we see.

Simultaneous Contrast. How red is red? That depends in part on its context. We see colors in relationship to other colors in our field of vision. The appearance of any one color is modified by the presence of other colors.

Simultaneous Contrast is the tendency for colors at the opposite ends of the primary scale to perceptually "jump" when placed together; for example, red and green, yellow and violet, orange and blue.

Simultaneous as existing, occurring, or operating at the same time.

11-03-00

The most famous example of simultaneous lightness contrast is the Hermann grid, discovered by the popular
illusionist L. Hermann in 1870. Look at any intersection in the grid, and gray dots seem to appear at the others. This is virtually the same effect as above. Between the black squares, the white lines are surrounded on two sides by black so appear very light. At the intersections, however, the white is only surrounded by black at corners. Because the contrast is smaller, the intersections appear darker (more grayish) than the lines.

http://www.michaelbach.de/ot/lum_herGrid/index.html

11-03-01	The four inner squares are equally gray. But their luminance changes in the surrounding squares.
	.	R	G	B
	Inner squares Black square Dark-gray square Light gray square White square	128 0 85 170 255	128 0 85 170 255	128 0 85 170 255

11-03-02	The green dot on the red background seems larger as the red dot on the green background.
	The yellow dot on the blue background seems larger as the blue dot on the yellow background.
	The white dot on the black background seems larger as the black dot on the white background.

11-03-03

Both red dots have the same dimension and even the color red is the same.

11-03-04

All circles have a common center.
These concentric circles look like a spiral.

This visual illusion is called:

The James Fraser Illusion
or
The Twisted Cord Illusion
or
The False Spiral

Link to Simultaneous Contrast:
http://colorusage.arc.nasa.gov/Simult_and_succ_cont.php

Please be so kind to enter any questions or remarks in my Guestbook

Last update
2010-05-18