2. Fundamental:
• Type consists of symbols derived from varying widths of
lines. We communicate via type by translating the symbols
into language and meaning. This is linear communication.
• Pictures are non-linear communication. We take in the
image holistically, and translate it into meaning by making
comparisons with that which we recognize from our life
experience.
• Accurate reproduction of visual images (pictures) must
involve varying shades, from light to dark
• However, in printing processes there is either ink, or no
ink
• No practical reproduction process is able to reproduce
infinite shades from light to dark
3. Therefore
• Any reproduction process using current
technology must trick the eye into seeing shades
from dark (pure color or ink) to light (no color or
ink)
• Current technology utilizes screening, which
breaks pure color into dots that simulate shading
5. The amount of shading
is measured in percentages
of the pure color
100 % black 50% black 10% black
6. Drop-out
Or Reverse
You can place type within a tint block, but you
must create contrast with the tint block. Doing this
is called creating a drop-out or a reverse.
9. Be wary of
backgrounds
When working with overprints and reverses, be careful to use
a neutral background. Failure to do so can have unfortunate results.
This mistake is common in web pages.
10. An attempt to use
a clever
background, with
resulting loss of
contrast, legibility
and readability
11. Gradients can backfire
A gradient is neither light nor dark,but a gradual transition
from light to dark. Reverses or overprints in gradients will
have bad results, if used carelessly.
12. Reproducing pictures
• You must use either the basic technology of
contrast, or the technology that creates tint blocks.
• Images created from contrast are called line art.
They are either simple outlines, with no shading,
or they use lines in combination to reproduce
shading.
• Etching is an example of this kind of picture
reproduction. The illusion of shading is produced
by many tiny lines.
13. Detail of an
etching by
Francisco
Goya
entitled
“They say
yes and
give their
hand to the
first
comer”
(1797)
14. Continuous tone images
• Images reproduced by using the technology that
creates tint blocks are called “continuous tone”
images, because they have the illusion of
continuous, unbroken shades from light to dark.
• To reproduce these images, the image must be
broken into dots, a technology called the halftone
process
• Any printed images will either be line art, or a
halftone image. There is no other practical
alternative in today’s printing technology.
15. Two ways to reproduce
pictures
• High-contrast images are converted
to line art
• Continuous tone images must be
translated into halftones
17. A halftone image
Note the dots. This example is a
very low-density screen. Compare
this to the screen used to make the
tint blocks in the earlier slides.
18.
19. Digital tools use
a different method
• Electronic processes break the image into pixels (picture
elements)
• These create shades of gray on the monitor screen, or
shades of colors
• The clarity of the image, called resolution, is measured by
pixels per inch (ppi). The greater the ppi, the finer the
resolution.
• However, the greater the ppi, the more computing space
needed to analyze the image.
• Typical web page images are 72 ppi; pictures meant to be
reproduced as printouts can be 200 or more ppi.
33. • If a screen image is printed, these pixels are
in turn reproduced as dots in printouts.
(Printer specifications will be in dots per
inch, or dpi.)
• The greater the dpi, the finer the screen and
the better the picture reproduction.
