DEFINITIONS
What is CMYK?
The CMYK color model (process color, four color) is a subtractive color
model, used in color printing, and is also used to describe the printing
process itself. CMYK refers to the four inks used in some color printing: cyan,
magenta, yellow and key (black). Though it varies by print house, press
operator, press manufacturer, and press run, ink is typically applied in the
order of the abbreviation.
The "K" in CMYK stands for key because in
four-color printing, cyan, magenta and yellow printing plates are carefully
keyed, or aligned, with the key of the black key plate. Some sources suggest
that the "K" in CMYK comes from the last letter in "black"
and was chosen because B already means blue.] Some sources claim this
explanation, although useful as a mnemonic, is incorrect, that K comes only
from "Key" because black is often used as outline and printed first.
The CMYK model works by partially or entirely masking colors
on a lighter, usually white, background. The ink reduces the light that would
otherwise be reflected. Such a model is called subtractive because inks
"subtract" brightness from white.
In additive color models such as RGB, white is the
"additive" combination of all primary colored lights, while black is
the absence of light. In the CMYK model, it is the opposite: white is the
natural color of the paper or other background, while black results from a full
combination of colored inks. To save cost on ink, and to produce deeper black
tones, unsaturated and dark colors are produced by using black ink instead of
the combination of cyan, magenta and yellow. It is used for printing, there is an example of cmyk.
What is RGB?
RGB (red, green, and blue) refers to a system for
representing the colors to be used on a computer display. Red, green, and blue
can be combined in various proportions to obtain any color in the visible
spectrum. Levels of R, G, and B can each range from 0 to 100 percent of full
intensity. Each level is represented by the range of decimal numbers from 0 to
255 (256 levels for each color), equivalent to the range of binary numbers from
00000000 to 11111111, or hexadecimal 00 to FF. The total number of available
colors is
In the Hypertext Markup Language (HTML), the color for a
page background or text font is specified by an RGB value, expressed with six
digits in hexadecimal format. The first and second digits represent the red
level; the third and fourth digits represent the green level; the fifth and
sixth digits represent the blue level. In order to actually display the colors
for all possible values, the computer display system must have 24 bits to
describe the color in each pixel. In display systems or modes that have fewer
bits for displaying colors, an approximation of the specified color will be
displayed.
In creating Web pages, the number of RGB values that are
recommended for use is considerably reduced - first, by the fact that many
displays can handle only 256 colors and, secondly, because PC and Mac Web
browsers. RGB is used for digital , screen monitors phones.
What are Pixels?
Pixel is basically a mixture of ‘Picture' and 'Element’.
Pixels collectively create images that one can see on a digital screen display.
Generally, the higher the pixel counts within a digital image, the sharper the
image. A digital camera usually produces better images because they produce a
higher pixel count. It makes the image more suitable for enlargements and
allows more possibility for image cropping. Pixels are a basic measuring unit
in computer imagery. It is used in cameras, screens, TVs, etc., anywhere an
image is displayed. It is also considered as a physical point in a raster image
or the smallest element that is displayed in an image. An image is often made
up of small pixels that come together to form a bigger picture. Pixels can also
be used as color dots to create a whole image, where pixels represent colors in
the image.
What is resolution?
The process or capability of making distinguishable the
individual parts of an object, closely adjacent optical images, or sources of
light
A measure of the sharpness of an image or of the fineness
with which a device (as a video display, printer, or scanner) can produce or
record such an image usually expressed as the total number or density of pixels
in the image <a resolution of 1200 dots per inch>
In Physics & Chemistry: The act or process of separating
or reducing something into its constituent parts: the prismatic resolution of
sunlight into its spectral colors.
The fineness of detail that can be distinguished in an
image, as on a video display terminal.
The amount of detail that the camera can capture is called
resolution. It is determined by the dimension of the unit of information
representing an image. In optics, resolution is the ability to distinguish two
separate objects. The resolution of a system is based on the minimum distance
at which the two objects can be separated and distinguished as individuals. The
resolution depends on the aperture of the instrument and the wavelength of the
observed light. The resolution of digital images can be described in many ways
including pixel resolution, spatial resolution, spectral resolution, temporal
resolution and radiometric resolution.
Resolution can be measured in 3 ways:
Sample per inch (spi, scanners)
Pixel per inch (ppi, monitors)
Dots per inch (dpi, printers)
EXAMPLE Notice when an image is magnified to its full
extent, it shows tiny squarethat make up the picture. These are pixels; these
pixels together make up the image that is being displayed. Screens and TVs that
are available these days come with a fixed pixel amount, which is given under
resolutions. This determines the quality of the image that would be available
on the screen. The higher the resolution, the higher the pixel count, which
results in a better image.
what are registration marks?
Marks made to a surface to help with alignment. A
registration mark is commonly used with printing to help ensure the print is
aligned properly.
. What is Bleeds?
bleed is printing that goes beyond the edge of the sheet
before trimming. In other words, the bleed is the area to be trimmed off. The
bleed is the part on the side of a document that gives the printer a small
amount of space to account for movement of the paper, and design inconsistencies.
Artwork and background colors can extend into the bleed area. After trimming,
the bleed ensures that no unprinted edges occur in the final trimmed document.
It is very difficult to print exactly to the edge of a sheet
of paper/card so, to achieve this, it is necessary to print a slightly larger
area than is needed and then trim the paper/card down to the required finished
size. Images, background images and fills which are intended to extend to the
edge of the page must be extended beyond the trim line to give a bleed.
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