Enter a value between
0 [Note 1] and 255 for
each colour component...

...then click to:

Red Green Blue
...and/or use sliders [Note 2] :
...and/or animate transitions through a colour intensity range:
Upper limit
Lower limit
Increment size [Note 3]
Increments/second [Note 4]
Simultaneous start/stop [Note 5]        
Want to test your ability to discriminate colours? If so,
choose a test colour...


Note 1: (Or leave box blank)

Note 2: Click to select and(a) drag, or (b1) release and use right/left device keyboard scrolling keys to move one increment at a time by (repeated) key presses, or (b2) move rapidly by holding the key down. 'Range' sliders not supported in versions of Internet Explorer below 9 (where they are rendered as another set of text input fields).

Note 3: You can increase the size of the colour intensity increments from the default value of 1 (which goes through all 255 levels of red intensity; values less than 1 can also be chosen; although fractional intensity levels will presumably not be displayed, the animation will be slowed.)

Note 4: You can adjust the speed of incrementing
(though higher values may not run as fast as expected (due to system limitations(?)):

Note 5: To start animations for two or all three colours simultaneously, click on the "Sim Start Setup" button, click one of the "More" or "Less" button pairs for two or all three of the colours (e.g. More Red, Less Green, More Blue), then re-click the original button, now labelled as "Start Chosen Buttons". To stop all animations simultaneously, click on the "Stop All" button.

Note 6: If you want to start with the original values as used for the display box background and tweak them gradually, clicking this button below will copy the numbers over automatically.

Note 7: See if you can discern the random single digit whole number in the same display box (top). (See also blog post on using this to explore background effect on colour perception.)