COLOR SUBTRACTION

Color subtraction can be observed under three conditions: 1) reflected light, 2) mixing pigments, 3) filters. In each case, the medium (reflecting surface, pigments, and filter) affects or modifies the light before it reaches your eyes. In each case the process called color subtraction will allow us to predict the color we see.

First identify all of the color subtractions. Here are the “formulas”. The subtracting color(s) were figured out by determining which colors were present and what colors were missing or subtracted.

SECONDARY COLORS:
YELLOW = GREEN + RED (the only primary color not used is BLUE therefore Yellow is -B subtractor)

MAGENTA = RED + BLUE (the only primary color not used is GREEN and therefore magenta is -G subtractor)

CYAN = BLUE + GREEN (the only primary color not used is RED and therefore Cyan is -R subtractor)

PRIMARY COLORS:

RED is a GREEN, BLUE subtractor

BLUE is a RED, GREEN subtractor

GREEN is a RED, BLUE subtractor

Identify the subtracting color(s) and subtract them from the light source.

R

E

D

White Light (RBG)

Red Light

-B -G

White light shines through a red filter. The red filter subtracts blue and green leaving red light that we see. White light(RBG) – B – G = red light

White Light (RBG)

Magenta Light (BR)

-G

M

A

G

E

N

T

A

White light shines through a magenta filter. The magenta filter subtracts green leaving red and blue light that we see as the color magenta. WL –G = Magenta (RB)

White Light (RBG)

Yellow Light (RG)

-B

Green Light (G)

-R

Y

E

L

L

O

W

C

Y

A

N

WL (–B) (–R) = G

White Light (RBG)

Yellow Light (RG)

-B

Red Light (R)

-B -G

Rdd Light (G)

-G

M

A

G

E

N

T

A

WL (–B) (–B-G) (-G) = R