Colour Theory Basics and Colour Comparison Exercise

written Oct 1999 being revised May 2006
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1   Preparation        

Use class material, books and other material from your school or local library, information sources on your computer files or CD's or the Web, to find out about the following aspects of colour theory. Once you are acquainted with these topics you will know enough to comment on your observations in the next following exercises.

2   Exercises in relative colour perception        

When you adjust the sliders on the left you will see that the rows of inner squares contain the same colour. When you adjust the sliders for the outer rectangles columns along the bottom you may see that the colours in the squares look somewhat different. It may help if you relax the focus of your eyes and allow the squares to come together. Experiment with different coloured backgrounds and different colours for the square/background pairs.

Experiment 1 - Red/Green

Experiment 2 - Green with CYMK

Change the columns to the green background sequence 80, 160 and 240. On row 1 set up Cyan=200, on Row 2 set up Magenta=200. Again note the variations between the columns. Look carefully at the edges of the internal squares and note if there is any border effect. Note in the comment box which of the colour combinations produces a "halo" effect around the box. It is easy to assume that it is some glitch in the video monitor which is causing odd edges in the boxes, but by adjusting the scales you may be able to see that it is your own perception that introduces the edge effects. When you have done Cyan and Magenta do a row for Yellow and a row for Black.
Green Background Difference between Columns 1 and 2 Difference between Columns 2 and 3
Row Cyan=200 Little Slight Strong Little Slight Strong
Row Magenta=200 Little Slight Strong Little Slight Strong
Row Yellow=200 Little Slight Strong Little Slight Strong
Row Black Little Slight Strong Little Slight Strong
Note the "halo" effects that you observe in this comment box. And also any observations that surprise you. Experiment with other combinations to find the strongest "halo" effects and note the "colour" of the halo. You may recall where you have seen these effects in nature - such as blue cineraria flowers against green leaves.
This is the end of the second exercise. Please enter your name here and press the SUBMIT button to post your results.

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