Color Theory - Ms. kropac...Did you know?! Your eyes have only 3 types of cells that can recognize millions of colours.! When you observe a colour, it is because different combinationsColor

Color Theory

Thursday, May 19, 16

Which colours is white light made of?Thursday, May 19, 16

Did you know?

! Your eyes have only 3 types of cells that can recognize millions of colours.

! When you observe a colour, it is because different combinations of these cells are stimulated.

! A TV screen uses a system of only three colours to create the effect of many different colours, just like the cells in your eyes.


Color Mixing

Color can be perceived either from 1) a luminous object (TV, monitor,

projector) using the Additive Approach

2) reflected pigment or ink (printouts, materials) using the Subtractive Approach


Additive Color Model


Additive Color Model! Used by luminous objects

ex. Computers, TV, projectors




! When light energy is added, a color appears brighter









! The additive primary colours are (RGB):






– Red – Green – Blue






– Red – Green – Blue



! Different percentages of red, green, & blue light are used to generate different colours









! White light is created when Red, Blue and Green are mixed together














! http://dev.physicslab.org/asp/applets/additivecolors/default.asp


http://dev.physicslab.org/asp/applets/additivecolors/default.asp






Our Eyes


Our Eyes


Our eyes use the additive colour approach, but how do we see colour if all wavelengths are coming in from the sun (white light)?


Green Surface

White lightGreen Light reflected

Blue Surface

Blue Light reflectedWhite light

White light

Black Surface

No Light reflected

Red Surface

White light Red Light reflected

White Surface

White lightWhite Light reflected

Objects absorb all colors except the color being seen, which is reflected


! Objects absorb all colors except the color being seen, which is reflected" White surface = all wavelengths

(blue, red, green) are being reflected" Black surface = all wavelengths are

being absorbed." Red surface = blue and green

wavelengths are absorbed, red is reflected

" Green surface = blue and red wavelengths are absorbed, green is reflected.




! Questions, why are clouds white?





! Why is it not a good idea to wear black in the summer?


Subtractive Color Model


Subtractive Color Model! Used in the print media

ex. inks, fabrics, paints, crayons, etc.




! When more color is added, a color appears darker





! The subtractive primary colours are (CMY): – Cyan





! The subtractive primary colours are (CMY): – Cyan – Magenta





! The subtractive primary colours are (CMY): – Cyan – Magenta – Yellow



# Secondary colours produced by CMY colours are – Red – Green


# Secondary colours produced by CMY colours are – Red – Green – Blue





! Different percentages of cyan, magenta & yellow light are used to generate different colours







! There is no way of making white by adding CMY colour sources, the paper/canvas must be white to start with.


Colour Blindness! 1 out of 10 men and 1 out of 200

women have some type of color deficiency.

! The most common type is mistaking red and green.

! The second most common type is mistaking blue and yellow




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Color Theory - Ms. kropac...Did you know?! Your eyes have only 3 types of cells that can recognize millions of colours.! When you observe a colour, it is because different combinationsColor