BENGAL COLLEGE OF ENGINEERING
AND TECHNOLOGY, DURGAPUR
A
Project Report
on
“Graph Coloring”
Submitted in the Partial Fulfilment of the Requirement for the
Award of the Degree of
BACHELOR OF TECHNOLOGY
In
COMPUTER SCIENCE AND ENGINEERING
Submitted by
SAJAN SUMAN , SNEH NAYAN, ANIMESH PRASAD
College roll no. :- 162095459, 162109525,162126648
University roll no. :-12500116031, 12500116017,12500116113
Subject : Design and Analysis of Algorithm(CS501)
Under the Guidance of
Mr.NagendraNathDubey
Assistant Professor, BCET
ABSTRACT
ACKNOWLEGEMENT
TABLE OF CONTENTS
INTROUCTION
WHAT IS BLEND MODE HOW IT WORKS
Blend modes (or Mixing modes) in digital image editing and computer graphics
are used to determine how two layers are blended into each other. , blending
modes are used to control how pixels in separate layers interact with each other.
The use of this feature is very effective since playing with layers you can
control how this or that layer will affect the look of the image and, accordingly,
what impact it will have on the viewers. Working with layers and blend mode
specifically, you should know about three color groups
The base color is the basic color of the image.
The blend color, which is applied with the painting or editing tools.
The result color is the one you’ll get in the end of your work.
To apply blending modes, a Photoshop document should have at least two
layers. These can be either two completely different images or a duplicate of the
one you are working with. To see the effect of the blend mode, you should
choose one of the offered solutions from the layers menu and apply it to the top
visible layer.
Blending modes can be applied either to images or brushes, meaning that
special effects will be applied to one specific area instead of the whole image.
PIXEL AND COLOUR COMPOSITION OF
PHOTOSHOP
A pixel is the smallest unit of digital image or graphic that can be
represented by a dot or smallest available square on the screen, it is
basically a logical unit in digital graphics which is combined to
represent a image , video ,text or any visible thing on a display.
In Photoshop a pixel is a 3 byte information about the colour
composition , luminosity, brightness,contrast etc of that particular
pixel.
24 bit colour pattern of photoshop
The colour composition of Photoshop consist of 3 channels of the 3
primary colours which are red,green and blue respectively . Each
channel has a memory size of 8 bit due to which each channel is
capable of having 256 different values which ranges from 0 to 255 in
decimal number format ,but in Photoshop the value is represented in
hexadecimal number system.
8 bit colour pattern for each primary colour
Unlike the real world where the colours are subtractive in nature the
colours of the Photoshop are additive which means for the less value ,
the colour will be darker and for the higher value the colour will be
lighter.
1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Bit pattern of 100% RED
0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0
Bit pattern of 100% GREEN
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1
Bit pattern of 100% BLUE
0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Bit pattern of 100% CYAN
1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1
Bit pattern of 100% MAGENTA
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0
Bit pattern of 100% YELLOW
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Bit pattern of 100% WHITE
As the pixel information memory has a size of 24-bits ,8-bits per
channel so the total unique colours it can represent is 16777216 which
ranges from 000000 to FFFFFF in hexadecimal number system. The
colour code 000000 represents 100% black and FFFFFF represents
100% white.
BLEND MODES
There are various blend modes available in photoshop ,atmost there are 27
blend modes in latest version of photoshop , which is categorized into 6
categories on the basis of type similarity.
NORMAL
At 100% Opacity the default “Normal” Blend Mode simply shows the
image on top, and we can’t see anything underneath it. When we drag
the Opacity down to 50% it makes the selected layer more transparent
and this allows us to see the image below the Normal Blend Mode
isn’t actually “blending” the two layers together, it’s simply making
the selected layer more transparent which in turn reveals the layers
below. But, even though it isn’t technically “blending” pixels, it is
still a very effective tool when making composite images. So, when
we drop our opacity on the White to Black layer down to 50%, we can
still see all of the tones, we simply see them at 50% opacity.
MULTIPLY
Multiply is one of the most popular Blending Modes in Photoshop. This
Blending Mode multiplies the luminosity of the base color by the blend color.
The resulting color is always a darker color. White produces no change, while
the black pixels remain. It combines the contrast and the luminosity of the top
and bottom layer together, which makes it a very useful Blend Mode that we
use frequently in compositing. Multiply Blend Mode creates far more image
contrast most noticeable in the 25-75% range when compared to the standard
Darken Blend Mode. Look to the Multiply Blend Mode when you want to
darken and add contrast to the underlying layer.Multiply can produce many
different levels of darkening depending on the luminosity values of the blend
layer, which make it a great Blending Mode for darkening images or creating
shadows.
Formula of multiply blend mode:Result = Base layer * Blend layer
Bit pattern Base layer
SCREEN Screen is another of Photoshop’s most popular Blending
Modes. The resulting color is always a brighter color. Black produces
no change, while the brighter pixels remain. The color from the
blend color is used. The luminosity (Image detail) from the base
pixels are used.
Screen can produce many different levels of brightening depending on
the luminosity values of the blend layer, making Screen, a great
Blending Mode for brightening images or creating
highlights.
Formula of screen blend mode:
Result = 1- (Base layer * Bend
layer)
DIFFERENCE
The Difference Blending Modes uses the difference of the base and
blend pixels as the resulting blend.
White inverts the colors of the base layer. It is the same result as
inverting the colors of the base layer by pressing Command I (PC:
Ctrl I).
Black Produces no change, while dark grays apply a slight darkening
effect.
This blending mode can be extremely useful for aligning layers with
similar content.
Difference is the eighth and final Blending Mode that react differently
when Fill is reduced compared to Opacity.
COLOR Creates a result color with the luminance of the base color
and the hue and saturation of the blend color. This preserves the gray
levels in the image and is useful for coloring monochrome images and
for tinting color The Color Blending Mode preserves the luminosity
of the base layer while adopting the hue and saturation of the blend
layer. Color is the ideal Blending Mode for coloring monochromatic
images.
Also, Color, along with the Luminosity Blending Mode, is the second
pair of Commuted Blending Modes.
If you apply the Color Blending Mode to the blend layer, you will get
the same result, as when you apply the Luminosity Blending Mode to
the Base layer, then reverse the order of the layers.
OVERLAY
Overlay is another of Photoshop’s most widely used Blending Modes. It is a
combination of Multiply and Screen with the base layer always shining through.
Overlay uses the Screen Blending Mode at half strength on colors lighter than
50% gray. And the Multiply Blending Mode at half strength on colors darker
than 50% gray. 50% gray itself becomes transparent. Also, note that “half-
strength” does not mean,Opacity at50%.
In simple words If the colors on the blend color are darker than the base
they are multiplied. If they are lighter they are screened. This produces
saturated colors and pleasant contrast. Blending with 50% gray has
produces no change.
Another way of thinking about Overlay is by thinking of shifting mid-tones.
Dark blend colors shift the mid-tones to darker colors, light-tones shift the mid-
tones to brighter colors.
One difference between the Overlay Blending Mode and the other Contrast
Blending Modes is that it makes its calculations based on the brightness of the
colors in the base layer. All of the other Contrast Blending Modes make their
calculations based on the brightness of the blend layer.
Overlay, alongside Hard Light, is part of the first set of Commuted Blending
Modes in Photoshop. A set of commuted Blending Modes will give you the
same result when you apply one Blending Mode to the blend layer, as when you
apply the corresponded Commuted Blend Mode to the base layer, and then
reversing the order of the layers.
CONCLUSION
After working on this project we conclude that photoshop is a very powerful
tool for creating graphics and editing images.photoshop has various tools like
brushes , selection tool , cropping tool,alignment tool etc to perform many
different operations and specially about the blend modes which are applicable to
whole image or a part of image or on an individual pixel of the image , the each
blend mode takes the same information but treat it as different types and apply
the applicable algorithm to create new pixel information for the data taken from
base layer and blend layer
REFERENCES
