Why There Are Color Differences in Printing from
Your PC
By Paul Curran
This article describes the basic properties of
color, what the relationships are between them and
the differences between what you see and what you
actually get using your inkjet cartridges.
Properties
Most of you will have come across these three; Hue,
Saturation and Brightness; if you have ever messed
around with color settings of your images.
Hue: For example; blue, green and violet are all
hues. They are colors. The dictionary definition of
'Hue' is; "the attributes of colors that permits
them to be classed as red, yellow, green, blue or an
intermediate between any adjacent pair of these
colors."
Saturation: This refers to how vivid the color is.
The higher the amount of gray relative to the amount
of hue, the less vivid it will be.
Brightness: Relates to the relative darkness or
lightness of the color.
In 1905 American artist A. Munsell published a color
measurement system, naming the three parameters,
Hue, Value and Chroma (Hue, Saturation and
Brightness as above). This three dimensional
relationship resulted in color identification in
this format, for example; 7.5YR 7/12. Here we have a
yellow-red hue tending with a value of 7 and a
chroma of 12. There are 40 pages in the book
covering all colors in the complete Munsell system.
Monitor and printer color production
Printer
Printer colors are produced from inkjet cartridges
emitting minute patterns of ink dots placed on
paper. All colors that you see come from just four
colors; cyan (C), magenta (M), yellow (Y) and black
(K).
As an aside, a mixture of cyan, magenta and yellow
should produce black, but in reality a touch of
black is needed to get it.
Monitor
A phosphor is a substance that emits light when
subjected to radiation. Color phosphors are
illuminated with electrons in your monitor and hence
images are produced. There are three colored
phosphors in each pixel on the screen; red (R),
green (G) and blue (B).
Monitor and printer color differences
As will be aware, the printed output you receive
hardly ever matches exactly that seen on your
monitor 100% of the time. This is because the way
that color is produced is different and the range of
colors that are produced is different between the
monitor and printer, as described above.
There are ways to get a closer match. You can
experiment with printer driver settings or use image
editing/color management software to help match up
the two.
Printing Process
Most inkjet printers can't produce variations of the
three primary colors so they employ a process called
'halftoning' to represent the thousands of colors
needed. The two methods used for this are
'Dithering' and 'Error Diffusion'.
With 'dithering', different colored ink dots are
aligned to give the appearance of neutral
colors...suitable for large areas of color such as
in graphs and bar charts. There are often additional
settings such as 'Coarse Dithering'...for images
with limited detail and shading, and 'Fine
Dithering' for images with significant amount of
detail.
With 'error diffusion' inkjet cartridge dots are
merged with surrounding color dots to produce
natural colors with the possibility of subtle color
gradation. Ideal for detailed images or photos.
If there is only text to print then 'No Halftoning'
should be selected.
When scanning, be aware that it will be more
difficult to get a good match because the scanner
will make the image using the CMYK data format, then
RGB on the monitor and finally changed again to the
CMYK data format via the printer.
This article may be reproduced in its entirety
provided the resource paragraph below is included
and all urls kept active.
(c) Paul Curran, CEO of Cuzcom
Internet Publishing Group and webmaster at this
cheap ink cartridge & laser toner
store, providing
discounted brand name compatible ink cartridge and
laser toner supplies. Sign up for the feed on our
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Article Source:
EzineArticles.com
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