A clear visualization of RGB and CMY color model. How they work and what are their color elements.At the end, you also find the equation of calculating and converting them.

1. RGB AND CMY
COLOR MODEL

2. GROUP MEMBERS
• Nazmin Nahar Nipa (133-15-2969)
• Sheikh Maruf Hossain(133-15-3051)
• Irteza Rahman (133-15-3057)

3. INDEX
• RGB and CMY color model
• Basic Examples
• Differences
• RGB to CMY and CMY to RGB conversion

4. RGB COLOR MODEL
• RGB color stands for RED,GREEN and BLUE. This color
model is used in computer monitors, television sets,
and theater. It's an additive color model.
• Additive color model means is that where we can
combine these three basic color in various ways to get
a new color.

5. RGB COLOR MODEL CONT.
When we will combine
RED+GREEN+BLUE=WHITE
[colors result from transmitted light]
We will see example later..
R G B (Red, Green ,Blue) is of 8-bit each.
Thus maximum possible range by individual is
0-255 (as 2^8 = 256)

6. CMY COLOR MODEL
A subtractive color model.
CMYK refers to the four inks used in some color
printing: cyan, magenta, yellow and key (black).
Subtractive because, The ink reduces the light
that would otherwise be reflected. Inks
subtract brightness from white.
Represent by value only 0 or 1
0 = no color
1= full color

7. EXAMPLES RGB
WHITE(max)
While we combined
R(255)+G(255)+B(255) =W
“+” means additive
We get white while intersecting
C (cyan) = G + B
M (magenta) = R + B
Y (yellow) = R + G

8. EXAMPLES CMY
“-” means subtractive
C (cyan) = W - R
M (magenta) = W - G
Y (yellow) = W – B
Key color black(max)

9. DIFFERENCES BETWEEN RGB AND
CMY (SIGHT DIFFERENCE)

10. DIFFERENCES BETWEEN RGB AND
CMY CONT.
CMYK is a four-color mode that utilizes the colors cyan,
magenta, yellow and black in various amounts to create
all of the necessary colors
RGB is an additive type of color mode that combines the
primary colors, red, green and blue, in varying levels, to
create a variety of different colors.
RGB is vibrant
Whereas CMYK is not vibrant but good for reading

11. DIFFERENCES BETWEEN RGB AND
CMY CONT.
In RGB, when all three colors are combined and displayed
to their full extent, the result is a pure white.
In CMYK, when the first three colors are added together,
the result is not pure black, but rather a very dark brown.
CMYK is the primary color model used by color printers.
RGB is the typical color model used on electronic devices
such as computers, theaters etc.

12. CONVERSION POLICY
(RGB TO CMYK]
There is a core formula if we want to convert.
The R,G,B values are divided by 255 to change the range from 0..255 to 0..1:
• R' = R/255
• G' = G/255
• B' = B/255

13. CONVERSION POLICY
(RGB TO CMYK] CONT.
• The black key (K) color is calculated from the red (R'), green (G') and blue (B') colors:
• K = 1-max(R', G', B')
• The cyan color (C) is calculated from the red (R') and black (K) colors:
• C = (1-R'-K) / (1-K)
• The magenta color (M) is calculated from the green (G') and black (K) colors:
• M = (1-G'-K) / (1-K)
• The yellow color (Y) is calculated from the blue (B') and black (K) colors:
• Y = (1-B'-K) / (1-K)

14. EXAMPLE
• Lets think There is RGB value for violate(100,50,150)
• We want to convert it into CMYK
According to formula….
R’ =100/255 =0.392
G’ =50/255 =0.196
B’ =150/255 =0.588
Lets find the key for CMY
K =(1-0.588)=0.412 [Because this the largest value among given result]
(1-K) =0.588 [Will require later]

15. EXAMPLE
C=(1-R’-K)/(1-K) =0.333 [calculate from Red and black]
M=(1-G’-K)/(1-K) =0.667 [calculate from Green and black]
Y=(1-B’-K)/(1-K) =0. [calculate from Blue and black]
So,CMYK value for violate is (.333 , .667 , 0)

16. FEELING BORED?
WE ARE ALMOST FINISHING

17. CONVERSION POLICY
(CMYK TO RGB]
• CMYK to RGB conversion formula
• The R,G,B values are given in the range of 0..255.
• The red (R) color is calculated from the cyan (C) and black (K) colors:
• R = 255 × (1-C) × (1-K)
• The green color (G) is calculated from the magenta (M) and black (K) colors:
• G = 255 × (1-M) × (1-K)
• The blue color (B) is calculated from the yellow (Y) and black (K) colors:
• B = 255 × (1-Y) × (1-K)

18. EXAMPLE
Given CMYK value for violate is (.333 , .667 , 0)
and key value is 0.412
(1-K) =.588
We need to bring out RGB value from that
According to formula….
R =255 x(1-0.333) x .588 = 100
G =255 x (1-0.667) x .588 = 50
B =255 x (1-0) x .588 =150
So,RGB value for Violate is (100,50,150)
If you want to calculate these problem online
Go to http://www.rapidtables.com/convert/color/rgb-to-cmyk.htm

19. THANK YOU
References:
www.rapidtables.com
www.google.com
www.wikipedia.com