27Technical Information                                           Page 1 of 3   The COLOR AND ILLUSIONS program allows you to examine several interesting     aspects of color perception and optical illusions.  There are several basic   requirements for the program to operate efficiently.  First, you will need a  VGA screen.  This high-quality screen allows high definition graphics colors  to be presented.  A mouse is also helpful, but is not essential.  You should  note that no two screens are identical in the presentation of color.          Consequently, you should experiment with the brightness and contrast controls of your monitor in order to achieve the best effect.                                                                                                        27Technical Information                                           Page 2 of 3   All programs are activated using the drop menus in the program.  The menus    can be activated using the KEYBOARD or the MOUSE.                             KEYBOARD:  To use the keyboard to activate the drop menu, press the control      key (CTRL) and the letter of the menu item.  The menu list will be            printed.  Use the cursor control keys ( or ) to highlight the option you    want press  and then press the ENTER key.                                  MOUSE:  To use the mouse, move the cursor over the menu option you want and      click the left button.  The menu list will be printed.  Move the cursor to    the option you want and then click the left button.                        27Technical Information                                           Page 3 of 3   The option you select will begin immediately.  If you have questions about    how to operate the demonstration, press the 'H' key or move the cursor to the word 'Help" and click the left button.  To exit the demonstration, press the  'M' key or move the cursor over the word 'Menu' and click the left button.                                                                                                                                                                                                                                                                                                                                                                                                          27Afterimages                                                     Page 1 of 2   This simulation allows you to experiment with the color afterimages. Color    afterimages are a 'phantom' image that people perceived after staring at a    colored image.  The afterimage is the complementary color of the original     image.  In this program, you will be able to test several afterimage effects: The Simple Afterimage and The Saturation Change Afterimage.  The program      allows you to change the type of afterimage demonstration and the color of    the image.  Once you select the demonstration color, the program will begin.  Stare at the center of the screen.  You will see a small clock that                                                                                         27Afterimages                                                     Page 2 of 2   presents the time that you have stared at the screen.  For the best effects,  stare at the clock for at least 30 seconds. Staring at the screen for longer  times will increase the quality and magnitude of the effect.  When you are    ready to seen the afterimage, press any key on the keyboard.  The screen will be cleared and you should see an after image floating around your visual      field.  Blinking your eyes will some times cause the afterimage to appear     brighter.                                                                                                                                                                                                                                 27Cafe Illusion                                                   Page 1 of 1   This is an interesting illusion where straight appear to bend and squares     seem to change their shape.  The illusion gets its name because it first      appeared in a cafe in which white tiles were placed in a pattern that         the illusion.                                                                                                                                                                                                                                                                                                                                                                                                                                                                       27Color Mixing I                                                  Page 1 of 3   This demonstration allows you to experiment with ADDITIVE color mixing.       Additive color mixing occurs when the effects of two or more lights are       combined, or added together.  An example would be to have three projectors    casting a different colored light onto a white screen.  The color that the    three lights make is the sum of the three colors.  The Additive color mixing  is different from SUBTRACTIVE color mixing.  In additive color mixing, lights are added together.  In subtractive color mixing, color is removed from light.                                                                                                                                                            27Color Mixing I                                                  Page 2 of 3   When this program begins there will be a black rectangle to the left of the   screen and three color controls on the right of the screen.  The color        controls allow you to vary the amount of RED, GREEN, and BLUE light.  The     left rectangle will display the color you create.  According to color theory, you should be able to create any color by mixing various amounts of the       primary colors, red, green, and blue.                                                                                                                                                                                                                                                                                   27Color Mixing I                                                  Page 3 of 3   To operate the program, move the mouse to the color control you want to       change.  You can use the arrows at the top or bottom of the screen to make    small changes in the color.  An alternative is to put the mouse arrow into    the color bar and click at the level you want.  The color will automatically  be readjusted to the level you select.  To quit the program, click on the     word, MENU or press the letter M.                                                                                                                                                                                                                                                                                       27Color Mixing  II                                                Page 1 of 4   This program is allows you to demonstrate a component of the opponent process theory of color vision.  Two colors are said to be opponent colors when       adding them together produces a gray color.  For example, yellow and  blue    are opponent colors.  When yellow light is added to blue light, white light   is perceived.  You may want to refer to the COLOR WHEEL display in this       program package.  The color wheel presents the spectrum of colors from red to purple.  Colors on the opposite sides of the circle are known as opponent or  complementary colors.                                                                                                                                       27Color Mixing  II                                                Page 2 of 4   When the program begins, there are two small squares on the upper left of the screen.  The small square on the right of the screen is the match color       created by the computer.  You can change the match color by clicking the      mouse on the left or right arrows.  As the color changes, the proportion of   red, green, and blue light in the match color is presented.  The small box on the left is the complementary color you create by changing the level of red,  green, and blue light using the color control bars.  The large square on the  left is the additive mix of the colors presented in the smaller squares.                                                                                    27Color Mixing  II                                                Page 3 of 4   To operate the program, select a match color (represented in the small right  square).  Then, using the color control bars, create a complementary color    that causes the large square to appear gray.  The colors in the match square  range from red to violet, with each change representing a 10% change in one   or more of the colors.  Different color combinations create different shades  of gray.  Some colors such as yellow and blue seem to produce a white light.  Other colors such as green and violet seem to create a dark gray.  The shades of gray result from the differences in the brightness of the different colors.                                                                              27Color Mixing  II                                                Page 4 of 4   When you are mixing colors, try to a gray color with no hint of color. Once   you have created a perfect gray, you have found the complementary colors. You may want to record your DATA and compare it to the data collected by  others. This demonstrations is a simulation of an experiment conducted by Leo Hurvich and Dorothea Jameson (1957, Psychological Review, 64: pp 384 -404).                                                                                                                                                                                                                                                                                                                                   27Color Wheel                                                     Page 1 of 1   The color wheel represents a series of hues ranging from red to violet.  The  outer-most rings have the greatest saturation.  In other words, there is      little white light in color.  Moving toward the center of the ring, the       colors become more saturated until they appear white.  Colors on opposite     sides of the wheel are considered to be complementary colors.  This is, when  these colors are added to each other the combined light appears to be         achromatic (a light without color, such as gray).                                                                                                                                                                                         27Herman Grid                                                     Page 1 of 2   This program allows you to experiment with the Herman Grid.  When you stare   at a Herman grid small and faint dots appear at the intersection of the       blocks.  These dots disappear when you stare at the dots.  For the experiment,determine what happens to the effect when the color and size of the squares   and of the background is changed.  For example, will the dots continue to     appear as the gap between the squares is increased?  What will happen when    the color of the background and color of the squares is changed?                                                                                                                                                                          27Herman Grid                                                     Page 2 of 2   The variables that you can manipulate are:                                     BOX SIZE: Clicking the mouse on these controls will increase of decrease the            size of the squares in the grid.                                   BOX COLOR: This option changes the color of the squares.  There are 73 colors            from which to choose.                                               GAP SIZE: The gap size changes the space between the squares.  The size of              the squares is kept constant, however.                             GAP COLOR: This option changes the color of the background.                                                                                                 27Glowing Axes                                                    Page 1 of 1   This simulation presents an interesting illusion based on contrast effects.   The display is a series of overlapping rectangles of the same color.  The     central most rectangle is the brightest with each surrounding rectangle       appearing darker.  Although each rectangle is of uniform color and            brightness, the corners of the rectangles appear to 'glow'.  You can change   the color of the rectangles, and the glow will continue to appear.  You can   also have the computer randomly rearrange the brightness of the rectangles or use randomly selected colors for each rectangle.  These options  cause the    effect to be lost.                                                            27Mach Bands                                                      Page 1 of 1   The Mach Band Program will present 14 vertical bars.  The bars vary in        brightness from black to white.  Clicking on the color arrows, you can change the color of the bars.  Within each bar is a gray circle.  You can change the brightness (black to white) of the circle by clicking on the circle shade     arrows.  Each bar is a uniform brightness and color.  You are likely to see a 'boarder' at the edge of each bar, however.  This perception is due to the a  contrast effect and the way the visual system operates.  See the manual for a more detailed explanation of this effect.                                                                                                                   27McCollough Effect                                               Page 1 of 3   This program allows you to replicate the McCollough Effect Experiment.  The   program allows you to change the default features for the program.  Once you  have selected the desired features, the simulation will begin.  During the    adaptation phase of the experiment you will be shown a repeated series of     'slides'.  The first slide consists of vertical bars on a colored back-       ground.  The second slide consists of horizontal bars on a colored            background.  After the adaptation phase you will be presented with a test     pattern that contains both vertical and horizontal bars.                                                                                                    27McCollough Effect                                               Page 2 of 3   COLOR FOR SLIDE 1:  The default color is RED.  You may select from an                             additional 13 colors.                                     COLOR FOR SLIDE 2:  The default color is GREEN.  You may select from an                           additional 13 colors.                                     PRESENTATION TIME:  This controls how long each 'slide' is presented.                             The default is 5 seconds.  The range is 1 second to 10                        seconds.                                                         TOTAL TIME:  This option controls the length of the adaptation phase.                      The range is 1 minute to 30 minutes.                      27McCollough Effect                                               Page 3 of 3   During the test phase, the computer will present a test pattern of vertical   and horizontal lines.  If the effect worked, you should see afterimages in    the test pattern.  You can change the test pattern by clicking the mouse on   the 'switch' option of the screen. To end the program, click the mouse over   the 'menu' option.                                                                                                                                                                                                                                                                                                                                                                                    27Movement Aftereffect I                                          Page 1 of 1   Using this program you will be able to create the Movement aftereffect.  This illusion is created when you stare at a moving object for a some time and     then stare at a motionless object.  You should have the illusion that the     stationary object is moving.  For this demonstration you will state at a      series of vertically-oriented lines that move from left to right across the   screen.  Stare at the screen to 30 or more seconds, then press 'S' to stop    the movement of the lines.  You should have the illision that the lines are   bending to the left.  If you choose, you can experiment by having the lines   move slower OR faster.                                                        27Movement Aftereffect II                                         Page 1 of 1   Using this program you will be able to create the Movement aftereffect.  This illusion is created when you stare at a moving object for a some time and     then stare at a motionless object.  You should have the illusion that the     stationary object is moving.  For this demonstration you will state at a      spinning spiral.  When the spiral is spinning, stare at the center of the     image for 30 or more seconds.  Once you have stared at the object, look at    something in the room such as someone's face, you should have the illusion    that their face is twisting or bending.  You can also stop the spiral by      pressing the 'S' key.  The spiral should appear to move on its own.           27Neon illusion                                                   Page 1 of 1   In this demonstration you should see a `glowing' illusion around the lines    that form the colored circle.  You can increase or decrease the space between the lines that form the grid.  The Background control chnges the brightness   of gray of the screen.  The Surround Color control varies the color of the    lines that are not a part of the colored ring.  The Line Color control varies the color the of the colored ring.                                                                                                                                                                                                                                                                                      27Simultaneous Contrast:Black and White                           Page 1 of 2   This program allows you to contrast effects for brightness.  When the program starts, the screen is divided into two adjoining squares.  Within each square is a smaller square.  At the bottom of the screen are controls that allow you to independently change the brightness of either smaller square or either     larger square.  The brightness can vary from absolute black to the brightest  white possible using your screen.  To demonstrate the contrast effect, change one of the large squares so that it is a dark gray.  Change the other outer   square so that it is a light  gray.  Next, try to adjust the smaller squares  so that they appear to be the same brightness.  The numbers at the bottom of  27Simultabeous Contrast:Black and White                           Page 2 of 2   the bottom of the screen indicate the brightness of each block.  You may      notice that the two smaller square appear  to be of the same brightness even  though the actual brightness values for these squares is different.  This is  due to the contrast effect.  See the manual for a more detailed explanation   of this effect.                                                                                                                                                                                                                                                                                                                                                                                       27Simultaneous Contrast:Color                                     Page 1 of 1   This program is just like the brightness contrast except that colors are      used.  In essence, your perception of the color in the smaller square is      influenced by the color in the larger square.  To experiment with this        effect, change the colors of the larger squares.  At the same time, make      sure that the color in the smaller square is the same.  Do the colors of      the outer square influence your perception of the color in the smaller        square?                                                                                                                                                                                                                                   