Why we learn color theory
Knowing how colors are created and how
they relate to each other lets you work
more effectively in all graphic programs such
g p p g
as Adobe Photoshop or Illustrator.
Instead of achieving an effect by accident,
you’ll produce consistent results
thanks to an understanding of basic color
describing wavelength in vacuum.
Wavelength = S
h Speed of light
d f li h
in vacuum / Frequency.
The s eed of light is the velocity
speed f li ht
of electromagnetic waves in a
vacuum, which is 300,000
km/sec Light travels slower in
other media, and different
wavelengths travel at different
speeds in the same media. When
light passes from one media to
another, it changes speed, which
causes a deflection of light called
What causes a rainbow?
In a rainbow, raindrops in the air act as tiny prisms.
The angle of bending is different for different
wavelengths of light.As the white light moves through the
two faces of the prism, the different colors bend different
amounts of light and, in doing so, spread out into a
Approximate wavelength (in vacuum)
and frequency ranges for the various
780 - 622
622 - 597
597 - 577
577 - 492
492 - 455
455 - 390
384 - 482
482 - 503
503 - 520
520 - 610
610 - 659
659 - 769
1 terahertz (THz) = 103 GHz = 106 MHz = 1012 Hz,
1 nm = 10-9 um = 10-6 mm = 10-3 m.
The white light is a mixture of the colors of the visible spectra.
How We See:
The First Steps of Human
Which part of your body lets you read the
b k of a cereal b check out a rainbow,
l box, h k
and see a softball heading your way?
Eyes t k i t
take in tons of i f
f information about
the world around you — shapes, colors,
movements and more. Then they send the
information to your brain for processing,
so the brain knows what s going on
outside of your body.
The retina is responsible for
receiving lights and colors,
and sending this data with optic
nerves to the brain.
Scientists discovered two different
cells in the retina: the rod cells and
cone cells. These cells were named
because of their shape as viewed in
the rod and cone cells were responsive to light.
the retinal cones are the color receptors of the eye; and the
retinal rod cells, while not sensitive to color, are very sensitive
to li h at l
light low l l
Go into a closet and decrease the light level. Soon you will see
only shades of gray. Slowly increase the light levels until you
can begin to see color.
That proves that the cells which are responsible for lights are
not sensitive to colors .
In the human eye, there are many more rod cells in
the retina than there are cone cells.
The number of rod cells and cone cells in animals is often related to
the animal's instincts and habits. For example, birds such as hawks
have a significantly higher number of cones than do humans. This lets
them see small animals from far away, allowing them to hunt for food.
Nocturnal animals, on the other hand, have relatively higher numbers
of rod cells that allow them better night vision.
Visual Pigments in eye
Pigments are found in cone cells.
There are three types of cone cells, each of which
contains a visual pigment.
These pigments are called the red, blue or
green visual pigment. The cone cells detect the
primary colors, and the brain mixes these colors
in seemingly infinitely variable proportions so
that we can perceive a wide range of colors
Primary Colors “RGB”
Primary colors are sets of colors that can be combined to
make a useful range of colors.
three primary colors are usually used, since human color vision is
th primary colors normally used are red, green, and bl and their
d blue, d th i
environment is the black vacuum. It is called Additive colors “phosphors
It combine to gives us the white light .
But in the practical we can’t use this colors in
Painting or printing, we need an ink not a light
So scientists discovered another kind of colors are
ca e Subt act ve colors.
called Subtractive co o s.
Additive color mixing
Subtractive color “CMYK”
For subtractive combination of colors, as in mixing of
pigments or dyes, such as in printing, the primaries normally
used are cyan, magenta, and yellow
and their environment is the white Paper.
It combine t gives us th white a non complete
bi to i
Black, So that Scientists add the black ink to this
Mode of colors.
Subtractive color mixing
The combination of any two primary colors creates a secondary color.
Usage of additive color in industry
Television and other computer and
video displays are a common example
of the use of additive primaries and
the RGB color model.
colors chosen for the primaries are a
technological compromise between
the available phosphors (including
considerations such as cost and
power usage) and the need for large
color t i l t allow a l
l triangle to ll
the color space that is generated is
called an RGB color space.
The spectrum “all
co o s vacuum”
colors in vacuu
which human eye can
The CIE 1931 color space
It defines monochromatic primary
colors with wavelengths of 435.8
nm (violet), 546.1 nm (green)
and 700 nm (red) The corners
of the color triangle are
therefore on the spectral locus,
and the triangle is about as big
as it can be.
No real display device uses such
primaries, as the extreme
wavelengths used for violet and
red result in a very low
Some Examples of color spaces
Search through internet.
Colors are made of value, hue and
By combining these properties together we
can create a special color .
s ecial c l r
- Value: determine how color is light or
- Hue: determine which direction of the
color spectrum is the color or wheel the
color is oriented to
- Saturation: is the value of color pigment.
Value the most important aspect of
The Rule number 1 : Value is relative “to other values”.
Value demands attention.
Value speaks softly.
Value annoys with noise
Value has magic visual powerful effects.
Value can elusive.
Value pops up with contrast.
Value offset from background.
Value defines the invisibles
Value is the edge that defines.
Value hide details
Value defined by g
Value plays with you
Value holds its own
Value ranges from black to white.
Value ascends and descends.
Value is pure visual definition .
Testing relative Value
Our eyes are typically drawn to point of
highest contrast .
The largest object o t e high co t ast
e a gest
of the g contrast
draw the most attention of the eye in
general, but not always.
Low contrast can move elements to the
background of the elements in the images
and lower the importance of that
The small gray rectangle in all figures is a same value
The value of values.
- Whit i not white
White is t hit
- Black is not black
Elements that create colors
Rule Number1 : Saturation is more intense in
large areas of color.
Desaturated text doesn’t read well in
saturated a large color background, unless
there is a large value difference.
Saturated text on a desaturated background
reads OK. But could be improved by value.
Saturated text flys off when the background
is completely desaturated. And more so
when it pops up with contrast.
Value of color :
each hue has a unique value at its peak
saturation point here we have a x-ray view of
each color’s value at their maximum
Value Of Colors
How to choose colors at hue point of view
Can you read the text in ease
way which i id thi area of
hi h inside this
If you convert it to grayscale mode
the text is all most unreadable
Because the values of text’s color
and the background’s color even
d h b k
The image cannot be display ed. Your computer may not hav e enough memory to open the image, or the image may hav e been corrupted. Restart y our computer, and then open the file again. If the red x still appears, y ou may hav e to delete the image and then insert it again.
Creating color systems and color
l i hi
Moving hues on the color wheel.
• Shifting colors
Adding Value + Saturation + Hue
• Toning colors
Mixing gray (tinting + shading).
Implementation of colors
RGB images use three colors, or channels, to reproduce
colors on-screen. In 8-bits-per-channel images, the three
channels translate to 24 (8 bits x 3 channels) bits of color
information per pixel. With 24-bit images, the three channels
can reproduce up to 16 7 million colors per pixel.
With 48-bit (16-bits-per-channel) and 96-bit (32-bits-perchannel) i
l) images, even more colors can b reproduced per
pixel. In addition to being the default mode for new
Photoshop images, the RGB model is used by computer
monitors to display colors. This means that when working in
color modes other than RGB, such as CMYK, Photoshop
converts the CMYK image to RGB for display on screen.
Converting between color modes
You can change an image from its original mode
(source mode) to a different mode (target mode).
When you choose a different color mode for an
image, you permanently change the color values in
g ,y p
the image. For example, when you convert an RGB
image to CMYK mode, RGB color values outside
the CMYK gamut (defined by the CMYK working
space setting in the Color Settings dialog box) are
adjusted to fall within gamut
As a result, some image data may be lost and can’t be
recovered if you convert the i
h image f
back to RGB.
About foreground and background colors
Choose colors i the toolbox
Choose colors with the Eyedropper tool
Color Picker overview
Choose a color with the Adobe Color Picker
Choose web-safe colors
Choose a CMYK equivalent for a non-printable
Choose a spot color
Change the color picker
Color panel overview
Select a color in the Color panel
Select a color i the S
l in h Swatches panel
Add and delete color swatches
Manage swatch libraries
Share swatches between applications
Color and tonal adjustments
Viewing histograms and pixel values
Understanding color adjustments
Adjusting image color and tone
Targeting images for press
Matching, replacing, and mixing colors
Applying special color effects to images
What is blending mode
We always found a blending mode in most
of graphic programs and wonder what it
So before demonstrate it we will make an
experiment with three circles and watch
out the result of blending it with the
There are three circle over colored
background, the first circle i 100% black, th
d th fi t i l is 100% bl k the
second one is 50% gray and the third is white
We will try to blend these circles with the base
colored background in some blending modes.
Watch out how it affect on appearance of each circle
To show you what each effect does I’ve blended the following two photos
Try to mix these layer with all blending modes and see the result:-
Bl d L
Demonstration of blending modes
How the Multiply blending mode works:
“multiplies the color values in the layer and divides the result by the maximum
pixel value of either 8 bit or 16 bit pixels. The resulting image is never brighter
than the original.”
Simply put: All white pixels in the blended layer disappear.
Effects of the Screen blending mode:
“multiplies the inverse brightness values of the colors in all layers.”
Simply put: All the black pixels in the blended layer disappear.
Effects of the Overlay blending mode:
“mixes colors between layers, preserving the highlights and shadows to reflect the
light and dark areas of the layer colors.”
Simply put: Blended layer adds intensity to the layer underneath.
The Dodge blending mode
“Brightens the resulting color based in the original color. The lighter the original
color, the brighter the resulting color. Pure black in original layer does not change
the underlying layer. Pure white in original usually changes the underlying color to
Simply put: Lightens overall while top layer colors bottom layer
The Burn blending mode
“Darkens the resulting color based on the original layer color. The darker the
original layer, the darker the resulting color. Pure white in the original layer does
not change the underlying color. Pure black in the original layer usually changes the
underlying color to black.”
Simply put: Darkens overall while top layer colors bottom layer
The Hard Light blending mode
“Multiplies or screens the resulting color depending on the original color. If
underlying color is less than 50% gray, the layer lightens it as if it were screened. If
underlying color is greater than 50% gray, the layer darkens it it as if it were
Simply put: Reduces contrast, adds color.
The Soft Light Blending Mode
Darkens or lightens resulting colors, depending on the layer color. If underlying
color is lighter than 50% gray, the layer lightens. If underlying color is darker than
50% gray, the layer darkens.’
Simply put: Vintage with color!
Difference blending mode
“subtracts the channel values of the layer and underlying colors and displays the
absolute value of the result.”
Simply put: In either layer, black has no effect and white inverts the other layer’s color.
layer s color
Darken Only blending mode
“Compares the channel values of the underlying and layer color and displays the
darker of the two. Can cause color shifts.”
Simply put: shows pixels from the blended layer unless the pixels underneath are darker.
Lighten Only blending mode
The Lighten Only blending mode is very similar, but with one obvious difference.
Adobe’s definition is that Lighten Only “compares the channel values of the
underlying and layer colors and displays the lighter of the two. Can also cause a
Simply put: shows pixels from the blended layer unless the pixels underneath are lighter.
Addition blending mode
“combining the color values of the [blended] layer and underlying colors. The
resulting color is lighter than original. Pure black does not change underlying color.
White in base layer is never changed.
Simply put: “lightens the base image, ignores black, and keeps the top layer’s color.”
“Creates resulting colors with the luminance and saturation of the underlying
colors and th h of th layer colors.”
d the hue f the l
Simply put: colors on top replace colors below. “change only hue for the new layer”
“creating resulting color with the luminance and hue of the underlying colors and
the saturation of the layer colors”.
Simply put: Top color determines saturation level for the layer below.
“create resulting colors with the “luminance of the underlying colors” and the
“hue & saturation of the layer colors”. This preserves the gray levels of the image.”
Simply put: colors on top replace everything but pure black below.