Chap46

 Explain the different types of colour.

In This Chapter, you’ll learn on:
 Different types of Colour Management System
o RGB Formula
o CMYK Formula
o Black & White
o Duotone
 How to convert between colour modes such as
o Black & White to Duotone
o RGB to Grayscale
o RGB to CMYK
o RGB to Indexed.
 Advantages of web-safe colour tools :
o 216 web-safe colours
o HTML colour codes
o Colour Matters / web-safe palette
o Colour Logic for web-safe colours
 Differences between process colour and spot colour in a
desktop publishing documents

 Color plays a vitally important role in the world in which we live.
Color can change actions, sway thinking, and cause reactions. It
can irritate or soothe your eyes, suppress your appetite or raise
your blood pressure.
 As a powerful form of communication, color is irreplaceable. Red
means "stop" and green means "go”. Traffic lights send this
universal message. Likewise, the colors used for a product, web
site, business card, or logo cause powerful reactions.
 Color models describe colors numerically. There are different
methods of describing colors numerically, and a color mode
determines which method or set of numbers to use to display and
print an image. Photoshop bases its color modes on the color
models that are useful for images used in publishing. You can
choose from RGB (red, green, blue); CMYK (cyan, magenta,
yellow, black) and Grayscale. Photoshop also includes modes for
specialized color output such as Indexed Color and Duotone.

 Black & White (Bitmap)
In bitmap images, pixels are either black or white. This allows for
incredibly small file sizes, but there is a corresponding loss of
image quality. Because pixels are either black or white, they
can appear jagged along the edges. At low resolutions, this
can lead to a "blocky" appearance. Images that just contain
only black and white dots should in most cases be scanned in
600 dpi to obtain a good quality. The exception is if the files
become too large to handle, 300 dpi is in most cases
acceptable.
 When converting a grayscale image to bitmap, the computer
analyzes each pixel, and "rounds" it to either black or white.
 In bitmapped mode, each pixel occupies 1 bit. A pixel can
either be the foreground or the background color. Bitmapped
mode is mainly used for scanned line art or for special fonts or
symbols to be used on the web.

 Grayscale
Grayscale is similar to bitmapped mode, but it stores shades
between foreground and back-ground. Photoshop supports
either 8 bit (256 shades) or 16 bit (65536 shades) resolution.
This is the universal mode for anything that does not need
colors.
 Grayscale images are 256 shades of gray. Each pixel is
assigned a brightness value that gives it the gray tone. Color
images can be converted to grayscale, as can grayscale
images be converted to RGB or Indexed Color modes,
though the color palette will be made up of gray shades.
When you know your final product is going to be grayscale,
it is best to work with them in color first, to get more of the
subtle tones that you may want, and convert it to grayscale
as a last step.

A grayscale
image at 8
bit color
depth.
Close-up of the grayscale
image. Notice that there
are black, white, and
shades of grey making up
the image.
Grayscale
image
converted
to bitmap
image at 96
dpi.
Close-up of bitmap
image. Notice that there
are no tones of gray, all
pixels are either black or
white.

 RGB
RGB stands for the colors Red, Green and Blue. RGB are the
colors that computer monitors, scanners and televisions use to
show colors.
 Most of the images people create are RGB, and when working
within your own office, it is generally the better choice when
creating and processing images. The computers colors (Red,
Green, Blue) is the best option for the web or electronic
publishing. They are also called additive colors. Advantages of
working in RGB mode include the following:
o You can save memory and improve performance because you
are working with fewer channels.
o The range of colors in RGB spaces is much larger than that of
CMYK spaces, so more colors are likely to be preserved after
adjustments.


 RGB
 When working in RGB color, you are working with 3
color channels. Each primary color, red, green and
blue, has its own channel, and the intensity of each
channel, on a scale from 0 to 255, contributes to the
color per pixel. Think of it as like mixing paints. The
proportions of red, green and blue used on the
painter's palette create a color. If a warmer shade is
desired, more red is added, with less green and blue,
etc.
 But since white is a pure color, it is created by
combining each channel at full intensity (255).


 Colors are created in the RGB mode by assigning values
ranging from 0 to 255 for each of the color channels. The
overlapping areas represent the colors created by full values
for each channel, in this case creating cyan, magenta, yellow,
and white.

 Even though you can perform all color and tonal
corrections in RGB mode and nearly all adjustments in
CMYK, you should choose a mode carefully. Whenever
possible, avoid multiple conversions between modes,
because color values are rounded and lost with each
conversion. If an RGB image is to be used on-screen,
you needn't convert it to CMYK mode. Conversely, if a
CMYK scan is to be separated and printed, you
needn't perform corrections in RGB mode.
 If you must convert your image from one mode to
another, it makes sense to perform most of your tonal
and color corrections in RGB mode and use CMYK
mode for fine-tuning.

 CMYK
CMYK stands for the colors cyan, magenta, yellow and black.
(in order to avoid confusing black with blue, its abbreviation is K
instead of B) . CMYK are the colors used for full-color printing
and is used more for commercial printing. If you look at a
magazine close up you will see tiny patterns of dots, these dots
are arranged in different patterns and sizes to fool the eye into
seeing colors that are not really there, e.g. brown etc. The
disadvantages are, the image is a 3 times larger than RGB, and
you will lose some brightness as CMYK does not support as wide
a tonal range as RGB. In this model four colors of pigment,
Cyan, Magenta, Yellow and Black are printed in patterns of
dots which our eyes mix to create the illusion of many different
colors.

 CMYK
Unlike the RGB model, CMYK is subtractive. While in theory
cyan, magenta and yellow could reproduce any color; black is
added to compensate for some impurities of the inks. CMYK is
the preferred color mode to use for color printing if - and only if
- your printer supports it. Other than that, it has no real
advantages.
 While cyan, magenta and yellow occur naturally, black has
been defined as the absence of color, but in the publishing
industry, in order to get true blacks, black had to be added to
the process.

 CMYK
Like the channels of RGB color, each color of CMYK is a channel, and
a pixel is assigned a percentage value of cyan, magenta, yellow and
black. A smaller percentage of a color equates to a smaller amount of
color available to the pixel. For instance, if a white area is desired, all
values would have a 0%. Red may have a low percentage of cyan,
high percentages of magenta and yellow, and no black. To create
darker colors, the mixing together of inks (higher percentages of color)
"absorbs" more light, therefore reflecting less and creating the darker
shades.

 Colors in the CMYK mode are created by assigning a
percentage to each color channel. The overlapping areas
represent the colors created by 100% of each color channel,
in this case creating red, green and blue. Notice however that
these shades of RGB differ from those in the image of RGB
color. This is due to the difference in the way CMYK interprets
and creates color.

 Printers use the CMYK color system. But because of the
difference in the way monitors see color and printers do, you
can get surprises when you go to print. This difference is in part
due to the nature of the mediums, and in part due to your
graphics adapter. Using higher quality adapters will lead to
less surprise.
 The important thing to remember about these color modes is
that what you see is NOT what you get. There are some colors
that can be displayed on screen that cannot be reproduced
in CMYK printing.

 Duotone
Duotone mode is very similar to grayscale. Duotones are used
when you want to add some depth or color to a black and white
image, or just get a trendy effect. A duotone lets you choose 2
ink colors on your image and will print as a 2 color job on the
press. Usually, it will be made up of black and one other color,
though it doesn't have to be. There is also a Tri-tone -which has 3
colors and a quad-tone that has 4. You can produce some very
sharp black and white (Grayscale) images with this and it is used
in photography books all the time.
 Because duotones use different color inks to reproduce different
gray levels, they are treated in Photoshop as single-channel, 8-bit,
grayscale images. In Duotone mode, you do not have direct
access to the individual image channels (as in RGB, CMYK, and
Lab modes). Instead, you manipulate the channels through the
curves in the Duotone Options dialog box.
 Duotone image will cut down the printing cost as its only consists
of two printing colors.

 Indexed Color
Index color images are created from RGB images.
RGB images can contain up to 16-million colors.
When an image is converted to index color, the
16-million colors are converted to 256. This color
reduction can create some image distortions as
well as some banding (less-than-smooth
gradations). Index color makes use of something
called dithering. Dithering is the process of using a
few colors to create the illusion of more colors
(not unlike the dot patterns used in CMYK
printing).
 Indexed color helps to reduce file sizes, which is
an important consideration for the web, while
maintaining the quality of the image.

 Indexed Color
Index color is a product of the Internet revolution and is
kind of a strange animal. If a graphic image has been
saved in this color mode then it can contain up to 256
colors and has 8-bit depth. That may sound like a lot but,
when you consider that an RGB image has 16 million colors,
256 doesn't sound like much.
 The objective in web graphics is to reduce file size as much
as possible while not abandoning image quality. One
wants smaller images so they will download to a browser
quickly.
 The attractive thing about index color mode is that 256
colors is the maximum the color mode can contain. It can
contain less (between two and 256). With care, a designer
can subtract colors from a graphic file so that it looks like a
full-color image while containing far fewer colors with little
quality loss.

Indexed Color
When dealing with index color, it's important to
keep in mind that, once an image's colors are
reduced, those colors are gone for good. If a 16-
color, index color image is converted back to full-
color, RGB mode, the image file size will increase
but the quality won't improve.
 Instead of storing the full color data for each pixel,
indexed mode only stores a pointer to an entry in a
color table. Photoshop supports up to 256 colors in
indexed mode. Indexed mode is used in the
popular GIF file format.

 Appropriate color modes for presentation media
 RGB Color mode
 (Red, Green, Blue) is the best option for the web or electronic
publishing.
 CMYK Color mode
 CMYK are the colors used for full-color printing and is used
more for commercial printing.
 Duotone
A duotone lets you choose 2 ink colors on your image and will
print as a 2 color job on the press. There is also a Tri-tone -
which has 3 colors and a quad-tone that has 4. You can
produce some very sharp black and white (Grayscale) images
with this and it is used in photography books all the time.
Indexed Color mode
Indexed color helps to reduce file sizes, which is an important
consideration for the web, while maintaining the quality of the
image.

 Conversion of Colour Mode From Black & White to
Duotone
 The actual Duotone Mode built into Photoshop was
designed to facilitate commercial printing needs so
some of the terminology such as "PANTONE" and
"process colors" might seem confusing to the casual user.
Don't let it bother you though since these distinctions
don't matter for typical home use.
 To create a true Duotone, first create a Channel Mixer
layer to achieve the black and white look you want or
use your own preferred black and white conversion
method. Then, flatten your image and use Image >>
Mode >> Grayscale to convert it to a single-channel
grayscale image. If you don't flatten the image before
going to grayscale, Photoshop will warn you that your
adjustment layer will be discarded in the conversion. Not
what you want. If you get this warning, be sure to select
"Flatten" instead.

Duotone
 Next, use Image >> Mode >> Duotone to begin the process of
toning your image. You can play with the color choices
yourself, but you are generally better off starting with one of
the many presets Adobe thoughtfully provided. To access
them, click on the "Load" button. Open the Duotones Presets
folder from the resulting window. From here, you should see
three folders: "Gray-Black Duotones," "PANTONE(R) Duotones,"
and "Process Duotones." In each, you will find a lengthy
selection of presets to play with. The specific differences
between each of these three types is not relevant to home
inkjet printing so feel free to play around with any or all of
them. Unfortunately, there's no facility to preview what each
preset does, so you'll need to open them to find out. Be sure
you have the Preview option checked in the Duotone Options
dialog so you can see the effect of each on your image.

Duotone
 Once you find something you like, you can feel free to tweak
the effect. The Options window has three main columns of
information: A curve for each color, the color itself, and the
name assigned to that color. To change colors, click on the
color square itself to open the Color Libraries dialog. To control
how that color is blended into the result, click on the curves
icon to the left of the color. If you are familiar with Curves in
Photoshop, you should be able to figure out what the Duotone
Curve control does, but it is odd that Adobe chose not to
make this identical to the regular Curves window. The grid
here is fixed at ten divisions on each axis. To the right of the
grid is a table allowing direct entry of what the resulting value
should be across the range of input values in ten percent
increments. Thus, each entry box on the right corresponds to
one of the vertical lines in the grid. Click on "OK" to return to
the Duotone Options window.

 Conversion of Colour Mode From Black &
White to Duotone
 When you finish setting your Duotone options, click "OK" to
complete the creation of your duotone. The results will be
applied immediately to your image. If you mess up the
Duotone Options to the point you wish you could start over,
simply hold down the Alt/Option key and the "Cancel" button
will turn into a "Reset" button. Click it instead of "OK" and the
Options dialog will revert to its default state.
 If you master duotones, Photoshop also supports Tritones
(three colors) and Quadtones (four colors). Simply select how
many colors you want to work with from the Duotone Options
drop-down list.

 Convert a color photo to Grayscale mode
 In this tutorial, we'll look at the absolute quickest and easiest
way of converting color photos into black and white in
Photoshop, which is by changing their color mode from RGB
to Grayscale.
 Normally, digital photos and images are in what's called the
"RGB" color mode. "RGB" simply stands for "Red, Green and
Blue", and the reason it's called the "Red, Green and Blue"
color mode, without getting into a lengthy discussion about
color theory, is because red, green and blue are the primary
colors of light. It sounds almost impossible, but every color our
eyes can see is made up of some combination of red, green
and blue. Also, every electronic device that either displays or
captures images, whether it's your tv, your computer monitor,
your scanner, or your digital camera, displays or captures
them using red, green and blue, since what they're actually
displaying or capturing is light, and red, green and blue are
the primary colors of light.


 Convert a color photo to Grayscale mode
 Open the photo you want to convert to black-and-white.
 Choose Image > Mode > Grayscale.
 If asked to discard color info, click OK. Photoshop converts the
colors in the image to black, white, and shades of gray.


 Convert a RGB color photo to CMYK mode
 When you take a photograph with a digital camera
or scan an image using a digital scanner, the
resulting file will use the RGB (Red Green Blue)
colour space. You can then view it on your
computer monitor and print it out using your
desktop printer and get a good representation of
the colour in the original image; this is because your
monitor and printer use the same RGB colour
space.
 If you need to have your photograph printed by a
commercial printer using 'full colour process
printing', you will have to covert RGB files to CMYK,
as a printing press uses the CMYK (Cyan Magenta
Yellow blacK) colour space.

 The problem is; the range of colours, referred to as gamut, that
can be produced using CMYK colour inks on paper, is a lot
smaller than what can be represented using RGB. This can
result in a photograph printing with some of the colours
changing hue and looking dull. This often happens to the
bright rich blue found in sky areas of an image.
 Thankfully, Adobe Photoshop, Illustrator and InDesign, are
design programs that provide CMYK Prepress presets
recommended for press setups across the world.
 In Photoshop, select 'Edit' then 'Color Setting...' and look at the
dropdown list under 'Settings'. Here you will see presets for
Europe, North America and Japan.
 Select a CMYK profile that best suites the final printing
conditions, for example, 'ISO Coated v2 (ECI)', which is used
for standard ISO printing based on the FOGRA39L
characterization dataset applicable to reference printing
conditions according to the international standard ISO 12647-
2:2004.

 Clicking on the 'More Options' button will allow you to set the
rendering intent to use when converting from RGB values to
CMYK. For continuous tone images such as photographs,
selecting 'Perceptual' will generally give the best results while
preserving the visual relationships of the source image.
 Once you have setup the best colour settings above, you can
open the RGB image you want to convert.
 A photograph from a digital camera will probably have an
embedded RGB colour profile (sRGB IEC61966-2.1). If
Photoshop presents a window with 'Embedded Profile
Mismatch' then select 'Use the embedded profile'.
 If you need to make any adjustments to the image or apply
any filters etc., do it now while the image is still in the RGB
colour space.

 To see which areas of the image that are 'out of gamut';
select 'View' - 'Gamut Warning'. Any colours that turn grey are
colours that can not be produced in the CMYK colour space
and Photoshop will have to select the nearest colour it can,
depending on the rendering intent you selected earlier.
 To covert from RGB to CMYK; select 'Image' - 'Mode' - 'CMYK
Color'. You will probably notice that some of the colours
change and become much duller. As shown in the images
above.


 Convert a Grayscale or RGB image to
Indexed color
 Converting to indexed color reduces the number of
colors in the image to at most 256—the standard
number of colors supported by the GIF and PNG-8
formats and many multimedia applications. This
conversion reduces file size by deleting color
information from the image.
 To convert to indexed color, you must start with an
image that is 8 bits per channel and in either
Grayscale or RGB mode.


 Choose Image > Mode > Indexed Color.
 Note: All visible layers will be flattened; any hidden
layers will be discarded.
 For grayscale images, the conversion happens
automatically. For RGB images, the Indexed Color
dialog box appears.
 Select Preview in the Indexed Color dialog box to
display a preview of the changes.
 Specify conversion options.
 Conversion options for indexed-color images
 When converting an RGB image to indexed color,
you can specify a number of conversion options in
the Indexed Color dialog box.


 Palette Type
 A number of palette types are available for converting
an image to indexed color. For the Perceptual,
Selective, and Adaptive options, you can choose using
a local palette based on the current image’s colors.
These are the available palette types:
 Exact
 Creates a palette using the exact colors appearing in
the RGB image—an option available only if the image
uses 256 or fewer colors. Because the image’s palette
contains all colors in the image, there is no dithering.
 System (Mac OS)
 Uses the Mac OS default 8-bit palette, which is based on
a uniform sampling of RGB colors.

 System (Windows)
 Uses the Windows system’s default 8-bit palette, which is
based on a uniform sampling of RGB colors.
 Web
 Uses the 216-color palette that web browsers, regardless of
platform, use to display images on a monitor limited to 256
colors. This palette is a subset of the Mac OS 8-bit palette. Use
this option to avoid browser dither when viewing images on a
monitor display limited to 256 colors.

 Uniform
 Creates a palette by uniformly sampling colors from the RGB
color cube. For example, if Photoshop takes six evenly spaced
color levels each of red, green, and blue, the combination
produces a uniform palette of 216 colors (6 cubed = 6 x 6 x 6 =
216). The total number of colors displayed in an image
corresponds to the nearest perfect cube (8, 27, 64, 125, or 216)
that is less than the value in the Colors text box.

 Local (Perceptual)
 Creates a custom palette by giving priority to colors for which
the human eye has greater sensitivity.
 Local (Selective)
 Creates a color table similar to the Perceptual color table, but
favoring broad areas of color and the preservation of web
colors. This option usually produces images with the greatest
color integrity.
 Local (Adaptive)
 Creates a palette by sampling the colors from the spectrum
appearing most commonly in the image. For example, an RGB
image with only the colors green and blue produces a palette
made primarily of greens and blues. Most images concentrate
colors in particular areas of the spectrum. To control a palette
more precisely, first select a part of the image containing the
colors you want to emphasize. Photoshop weights the
conversion toward these colors.

 Custom
 Creates a custom palette using the Color Table dialog box.
Either edit the color table and save it for later use or click Load
to load a previously created color table. This option also
displays the current Adaptive palette, which is useful for
previewing the colors most often used in the image.
 Previous
 Uses the custom palette from the previous conversion, making
it easy to convert several images with the same custom
palette.
 Number Of Colors
 For the Uniform, Perceptual, Selective, or Adaptive palette,
you can specify the exact number of colors to be displayed
(up to 256) by entering a value for Colors. The Colors text box
controls only how the indexed color table is created. Adobe
Photoshop still treats the image as an 8-bit, 256-color image.

 Color Inclusion And Transparency
 To specify colors to be included in the indexed color
table or to specify transparency in the image, choose
from the following options:
 Forced
 Provides options to force the inclusion of certain colors in
the color table. Black And White adds a pure black and
a pure white to the color table; Primaries adds red,
green, blue, cyan, magenta, yellow, black, and white;
Web adds the 216 web-safe colors; and Custom lets you
define custom colors to add.
 Transparency
 Specifies whether to preserve transparent areas of the
image during conversion. Selecting this option adds a
special index entry in the color table for transparent
colors. Deselecting this option fills transparent areas with
the matte color, or with white if no matte color is chosen.

 Matte
 Specifies the background color used to fill anti-aliased edges that
lie adjacent to transparent areas of the image. When
Transparency is selected, the matte is applied to edge areas to
help blend the edges with a web background of the same color.
When Transparency is deselected, the matte is applied to
transparent areas. Choosing None for the matte creates hard-
edged transparency if Transparency is selected; otherwise, all
transparent areas are filled with 100% white. The image must have
transparency for the Matte options to be available.
 Dithering
 Unless you’re using the Exact color table option, the color table
may not contain all the colors used in the image. To simulate
colors not in the color table, you can dither the colors. Dithering
mixes the pixels of the available colors to simulate the missing
colors. Choose a dither option from the menu, and enter a
percentage value for the dither amount. A higher amount dithers
more colors but may increase file size. You can choose from the
following dither options:

 None
 Does not dither colors but instead uses the color closest to the
missing color. This tends to result in sharp transitions between
shades of color in the image, creating a posterized effect.
 Diffusion
 Uses an error-diffusion method that produces a less structured
dither than the Pattern option. To protect colors in the image
that contain entries in the color table from being dithered,
select Preserve Exact Colors. This is useful for preserving fine
lines and text for web images.
 Pattern
 Uses a halftone-like square pattern to simulate any colors not
in the color table.
 Noise
 Helps to reduce seam patterns along the edges of image
slices. Choose this option if you plan to slice the image for
placement in an HTML table.

 Web Browsers Colors
 Web colors are colors used in designing web pages, and the methods for
describing and specifying those colors. Hexadecimal color codes begin
with a hash. Using the browser safe color palette is a choice you need to
make when you're creating a Web page or Web image. It is especially
important that you know what the consequences are for not using it.

 Example >>>
 You might use the color #dddddd for the background of a table. On
your monitor it would probably display as a nice neutral light grey. But
when you show it to a friend, it could look very different. Depending upon
how his monitor interprets the color it could look grey or it could look
green or some other color.

 What displays as light grey on a 24-bit, 16.7 million color monitor might
display as a really ugly greenish grey on a 8-bit, 256 color monitor.

 Why?
 This is because #dddddd is not a browser-safe color. "Browser Safe
Colors" are the 216 colors that can be viewed on 8-bit PC and Macintosh
monitors and looks the same (or close to the same).

 If you use browser safe colors, you can be sure that they will
not dither on these machines and your pages will look the way
that you intended them to look.

 8-24 bit Colors
 Personal computers with CRT monitors usually offer a choice of
settings for screen size and color depth.

 The amount of memory available to drive the display is fixed,
but users can choose a large screen resolution with a reduced
number of colors, or a smaller screen resolution with the
maximum number of colors.

 The table below shows the standard range of color modes.
Note that 32 bit color mode doesn't increase the number of
colors available, but it does allow video memory to be
updated faster.

Maximum Colors Bits Per Pixel Comments
256 8 bit 216 Web-Safe Colors
65 536 16 bit High Color
16 777 216 24 bit True Color
16 777 216 32 bit True Color
Web palette
The websafe palette consists of 216 colours that when displayed on a
256-colour (8 bit) monitor will be displayed as continuous flat colours.
These colours will be rendered as flat colours on both Windows and
Macintosh platforms - as to hue and saturation, Hexadecimal system
(base 16)

 CSS SHORTHAND
 When defining colours in CSS, hexadecimal codes
may be abbreviated to a single-digit for each of
the 2-digit pairs; e.g. #FF0033 may be abbreviated
to #F03.
 The hexadecimal counting system consists of 16
unique symbols;
 numbers from 0-9
 letters from A-F
 Counting in hexadecimal: 0 1 2 3 4 5 6 7 8 9 A B C D
E F, where 0 is null and F is the highest value.

 Specifying websafe colours (using hexadecimal notation)
 Colours in HTML are specified by a hash (#) followed by a six-
digit hexadecimal number. This number consists of three 2-
digit numbers corresponding to red, green and blue (RGB)
values.
 #XXxxxx = red
 #xxXXxx = green
 #xxxxXX = blue


 The websafe (216 colour) palette consists of a subset of the
possible hexadecimal combinations and is restricted to three
pairs of the same value at 20% increments, i.e.:
 00 33 66 99 CC FF
 Examples:
#000000 = black
#FF0000 = 100% red
#00FF00 = 100% green
#0000FF = 100% blue
#FFFFFF = white

 HTML Web Safe Colors Codes
 HTML colors are defined using a hexadecimal notation (HEX)
for the combination of Red, Green, and Blue color values
(RGB).
 The lowest value that can be given to one of the light sources
is 0 (in HEX: 00). The highest value is 255 (in HEX: FF).
 HEX values are specified as 3 pairs of two-digit numbers,
starting with a # sign.
 HTML colors are defined using a hexadecimal notation (HEX)
for the combination of Red, Green, and Blue color values
(RGB).
 The lowest value that can be given to one of the light sources
is 0 (in HEX: 00). The highest value is 255 (in HEX: FF).
 HEX values are specified as 3 pairs of two-digit numbers,
starting with a # sign.

 Web-safe Color Palette
 Although computers have a capacity for at least 256 colors,
only 216 colors are common to all older computers. Newer
computers are equipped with 64 thousand colors (16-bit) and
the highest quality systems deliver 16.7 million colors (24-bit).
However, approximately 10% of all computers are limited to
256 colors (8-bit).
 In the early days of the world wide web, the web-safe 216
color palette emerged. The image below is the most accurate
representation of the palette. Even though it's small, you can
magnify it after you download the graphic. It's a nice surprise
... so it's worth the time to download the graphic and open it
in any graphic application such as Photoshop.

 (You can save the graphic of this palette by following the
sequence for your computer's saving and downloading of a
graphic. In some cases, you can just drag the graphic to your
desktop, or alt click.)
 These are web-safe greens from the 216 color palette.
You are limited to a certain range of greens (including these) if you address
the web-safe range of hues.
If you use a green that is not one of the web-safe colors - and if someone's
computer is limited to 256 colors - the green will consist of a series of green
dots (from the web-safe greens) that approximate the color. For example,
the green below is not a web-safe green.

 You can see an exaggeration of the "dithering" - the patching
together of web-safe greens. This is how this color might look
on computers that have 8-bit color.

 The various colour classification system for print
Classification systems cover the many different ways of
classifying colors by bringing its parameters together in one
figure so that it is easy to specify a particular color by, for
example, its : -
 (1) HUE, or color of the rainbow or spectrum, Red, Yellow,
Green, Blue, Purple & intermediates,
(2) LIGHTNESS or DARKNESS (called Tone by painters or
Luminance by scientists), and (3) COLOUR FULLNESS (called
Intensity or Strength by artists and Saturation by dyers and
scientists).

 The basics of spot color printing process
Spot color is a method of applying a premixed color of ink
directly to the page. Spot color is useful for documents that
require only a few colors, such as newsletters, brochures and
stationery. Spot color is also used to match specific colors very
closely.
 Spot color inks come in a rainbow of colors, including some
specialty inks such as metallic and flourescent. Unlike CMYK or
process color which creates colors by laying down layers of
just 4 specific inks, spot colors are pre-mixed and you use one
ink for each color in the publication.
 There are different brands of spot color inks. In the United
States, the dominant spot color printing system is PANTONE.
The Pantone Matching System or PMS consists of over 1,000
colors of ink.

 Also Known As: PMS colors
 Spot colors can be used as an area of emphasis on a four-
color process job with the spot color generally printed as a
color on a separate plate and not as part of the four-color
process.
 Specialty inks can also be used as a spot color to provide
even greater emphasis to an area. Specialty inks can range
from fluorescent, fade resistant, opaque, and metallic inks.

 A Look at Spot Colors
 It's a good example of a Web graphic that would use spot
colors when it's printed.
 There are essentially three colors in the above graphic:
 Grey
 Green

 A Look at Spot Colors
 Each color is a spot color: black is one spot color; green is one
spot color; and purple is the third spot color. If there were two
more colors in this graphics, then most likely it would be more
economical to print it in process (also know as four color
process or 4/c). Since there's only three, it makes sense to use
spot colors.
 Many customers get into trouble because they don't realize
that black is actually a color, but it is. So if you have a graphic
that just uses blue,yellow and black, for instance, it's
considered a three color job.

 The basics of CMYK printing process
CMYK refers to the printing inks used in four-color process
printing. Cyan, Magenta, Yellow and Black are the colors used
to produce full-color photographs and designs. (An
approximate representation of these colors is below.)
 These colors can be combined and printed to emulate a wide
number of other colors. If you look carefully at a printed color
photograph in any magazine or book, you'll see that it's made
up of rows of tiny dots called a halftone screen. The dots work
together, at different angles, to fool your eye into seeing a full
spectrum of colors.
Cyan Magenta Yellow Black

For a graphics file to be printed in CMYK, it must be converted
or created in that color mode. When film is produced, a
different sheet of film is created for each color. For the
computer to tell the machine that produces the film, an
imagesetter, what to put on each sheet of film, the computer
image must be in CMYK format. Colors in a page layout
program must also be specified in percentages of the four
colored inks.
 So, why do we refer to these four ink colors as CMYK and not
CMYB? Well, quite simply, it's so that no one will be confused
into thinking that the last color is Blue rather than Black.

Printing an image in full-color is a complicated process
involving a number of steps. A basic knowledge of these steps
is not only essential for printers, but it is also important for
designers in planning and creating the best layouts and for
print buyers in understanding some of the issues that are raised
when purchasing color work.
 A mistake often made when submitting artwork for 4-color
printing is not converting the images to the CMYK color space.
This is needed so that the file can be separated into the four
colors (see example) so that a separate printing plate can be
made for each of the colors.
 Also Known As: 4-color | process colors

 The colour mixing and matching system of Pantones
To ensure that a printer uses exactly the color that a designer
intends, color systems were developed. The most common of
the spot color standards is the Pantone Matching System or,
PMS as it is more commonly known. All of the modern image-
editing, vector-drawing and page-layout programs come with
a full library of thousands of Pantone colors as part of the
program.
 In addition, designers will want to have a set of swatch books
that show printed examples of the colors and their codes.
Swatches are a more reliable method of matching or
choosing colors than doing so on-screen. This is because
monitors are illuminated by light behind them which makes
colors seem brighter on-screen than they are when printed on
paper. Also, colors on a monitor are created with red, green
and blue light (RGB) rather than mixed ink pigments.

In some cases, both spot color and process color can be used
on the same document. For example, a company brochure
may include color photos (process color) and a corporate
logo (spot color). Spot color applies a pre-mixed ink to the
page. This color is usually identified by a color system such as
the Pantone Matching System.
 Your printer or designer will often refer to a specific color using
a 'Pantone number'. If you are going to talk about colors in this
context, you need to know a few basics.
 The PANTONE MATCHING SYSTEM® is the definitive
international reference for selecting, specifying, matching and
controlling ink colors

It is used by artists and commercial printers to select, specify
and match colors very precisely. Many logos are created with
specific PANTONE Colors that can be very closely reproduced.
By using PANTONE Colors, designers can be confident that
their output will match their expectations.
 Each Pantone number relates to a unique color in a color
palette.
 It is not always possible to accurately match a 'Solid' color by
mixing cyan, magenta, yellow and black so a compromise is
therefore necessary. Pantone produce color guides to deal
with this issue. The Solid to Process Guide shows each Pantone
'Solid' color and its nearest 'Process' color equivalent.

 Before actually printing with color, it is necessary to
understand some of the factors that influence the
appearance of colors on a printed document. Listed below
are some of the important points to consider:
 Although color guides are a good tool for determining the
color that should be used, (such as spot colors), they should
be used only as a guide. There is no guarantee that the final
printed color will look exactly like the color in the guide. The
colors in the guides tend to fade, so the guides are usually
valid for about a year. The color swatches in a guide are
usually printed with a saturation that may be hard to achieve
on some applications.

 The type of paper on which color is printed has a huge affect
on the way the color appears. The same color will appear to
be quite different when printed on coated and uncoated
papers. The ink absorption rate, along with the brightness and
the color of different papers can result in significant changes
in the way color appears on different papers.
 There can be differences in ink pigments between different ink
manufacturers, which is another reason why it is difficult to
perfectly match the color in a guide. Most printers use ink from
one vendor, so they can usually expect consistency in the ink
they use.
 Lighting conditions affect the appearance of the ink color.
Differences in daylight during different times of the day and
differences in artificial illumination, such as fluorescent and
incandescent, can cause a wide shift in the appearance of a
color.

 Precise color matching can only occur when the preceding
factors are considered. A color viewing booth can be used in
order to accurately match the printed color with the
proof. Lighting conditions, materials, and the techniques
used, must be controlled in order to achieve the best results
when printing with color.

 Compare spot color and CMYK process, its advantages
and limitations
 Design choices will affect cost!
The cost of printing color documents is usually related to the
number of ink colors used. As process color requires four or
more inks, spot color can be cheaper if you use fewer than
four colors.
Spot color also has the advantage of printing a wider range of
clean, bright colors. If a color seems smooth and even no
matter how closely you look, it's probably printed with spot
color.

 Cons & Pros of spot color
If a designer needs to match a particular color (a logo color
perhaps) in a printed piece or has a limited budget, then spot
color is something to consider. Spot colors can also be used
alongside process (CMYK) colors for greater flexibility.
 Though some may view spot color printing as being much
more limited than CMYK printing, there are many interesting
possibilities.
 Two or more spot colors can be mixed to create interesting
colors and effects.
 Spot colors can be combined to create duotones, tritones
and quadtones that can be very effective and can add some
visual interest to otherwise grayscale images.

 Unfortunately, it's difficult to proof spot color jobs. Most
proofing systems use CMYK-based technology. Some
laminated proofs, which work by attaching colored sheets of
clear acetate, have some spot colors available but these are
often expensive.
 You can create the illusion of more colors in a job by using
shades of your PMS colors: these are known as screens,
shades, or tints. For instance, the golf ball in the GolfScapers
logo has gray in it. This is a shade (or tint) of black.

 Full Color Printing Vs. Spot Color
 Spot colour printing is not like full color process printing.
 In full colour process printing, four primary colors (cyan,
magenta, yellow & black) are used offering hundreds of
thousands of possible combinations to create full colour
printing.
 In spot color printing, single colors of ink are used that limit the
possible color combinations to those specific inks. For
example, if you had a spot color job that was being printed in
green ink, the only variations in color you will see is where the
ink has been "screened" to give the appearance of a lighter
shade. If you are printing with two colors, you are limited to
those two colors and the lighter shades available through
screening those two colors.

 Imagine your printing coming to life in full color. Our "Four
Color Process" makes it happen for you. People will sit up and
take notice when your product or service is presented in full
living color.
 What Is "Four Color Process"?
 It is the most common color system for print, producing full
color.
 The vast majority of magazines and color books are produced
using four-color process.
 Originally the artwork and originals were separated
photographically using filters to produce four printing plates.
Today's separation and production is carried out digitally.
 The four ink colors are Cyan (Blue), Magenta (Red), Yellow
and Black - often referred to as CMYK.


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