Before going into the details of the
subject let us understand the way of printing. If you have certain
printing job to be done you have to decide what type of color printing
you will go for. And the decision depends upon many factors like,
type of job, cost effectiveness, necessity etc. You have two options
available for printing any type of job in color.
1. Spot color
2. Process color
Spot Color
Whenever you require some particular color, it is
advisable to choose spot color method. If the job is corporate logo,
where the precision of the color is top most priority, you have
to go for spot color. Spot color is also known as custom color because
it is premixed to the desired color or the shade of the color prior
to printing. Next is a type of job you want to print. If it requires
one or two colors, the obvious choice will be spot colors. At that
time is the most cost effective method. Then there are some colors
which cannot be created by mixing process inks, like silver, copper
etc. For this type of work the spot color method is unavoidable.
Process Color
If the printing job is a full color photograph or
if the job requires more then three colors, process color is advisable.
Process colors are made by mixing the levels of CMYK i.e. Cyan,
magenta, yellow and black to get thousands of colors, which are
sufficient to produce smooth colored photograph. Sometimes in the
printing job both the methods are used. You may observe this in
the brochures where the photographs are printed with process colors
and the corporate logos are done with spot colors, as it requires
exact mach.
Halftones
Check out your newspaper. You will find smooth photographs
but if you watch them closely you will observe that they are made
up of small black dots of different sizes. This property of creating
continuous tone with black dots is called Halftoning.
To process the photograph it has to be converted into dots, which
is called halftoning process. The dots are created as follows.
The bright area, which is known as Highlights in image processing,
contains more white space with few small black dots. The gray area,
which is known as Midtones, contains medium sized black dots. The
dark area, which is known as Shadows, contains large black dots
with less white space.
These dots are arranged in a proper order. Traditionally they are
organized in a row per so many inches at predefined angles.
Using halftoning process it is possible to create smooth gray tones
with gray tint by controlling the arrangement of black and white
areas. While working with photographs, it is possible to create
smooth tones using proper size of dots.