Epson ES-800C Manual

What You
should Know
About Scanning

W HAT You S HOULD K NOW
A BOUT S CANNING
If you’re thinking about purchasing a scanner,
you may already know some of the ways they
can add visual interest and variety to all of your
projects. You don’t have to be a graphic artist
to inject extra punch in a special presentation,
newsletter, or brochure. You’ve probably also heard
that by using OCR (optical character recognition)
software, the scanner can create an editable text
file from any hard copy, such as a journal article,
fax, or legal document. But do you really know
how simple it is to use a scanner?
This booklet shows you how easy it is. Inside,
you’ll find the basics of how a scanner works and
see samples of scanned images. Useful tips address
common questions, such as how to determine the
right scanning resolution or make fine adjustments.
D ON ’ T M ISS T HIS S PECIAL O FFER !
When you purchase your Epson
®
scanner, send
a copy of your bill of sale in the envelope provided
in this booklet, and we’ll extend the warranty on
your scanner for an additional year, free of charge.
You receive two years of warranty
coverage with benefits like top-
notch technical support.

S CANNER T ECHNOLOGIES
Several types of scanners are available; the list
below summarizes some popular choices.
F LATBED S CANNER
Best suited for most business applications, this
scanner looks similar to a desktop photocopier.
You place a document on glass and close the
cover, and the scan head moves underneath it
along the “bed” of the scanner. Originally a gray
scale technology, color models are now just as
affordable, offering the widest range of uses in a
desktop system. A flatbed color scanner is ideal for
virtually all uses, from simple line drawings to
complex full-color illustrations and photographs.
H AND H ELD S CANNER
You hold this type of scanner in your hand and
run it over the image. The scan head is limited in
size, usually just four inches wide, so you have to
piece together wider images using your software.
While this is the least expensive of scanner
technologies, you’ll need a steady hand to avoid
distortions caused by shaky movement.
S HEETFED S CANNER
Developed specifically for use with OCR
applications, this scanner feeds sheets of paper
into the unit and scans them automatically. You
can get similar results by adding an optional
automatic document feeder (ADF) to your
flatbed scanner.

How S CANNERS W ORK
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All scanners convert areas of light and dark into
digital data for your computer. One of the most
versatile scanners for general office use is the
flatbed scanner. Scanning an image on a flatbed
scanner is a lot like using a photocopier. Here’s
how it works:
You place your document (a photo, book, or any
image that you want to scan) face-down on the
glass and close the cover.
Using the scanner software, you select a few
simple settings to adjust the way the image will
be captured; then you scan the document.
Inside the scanner, a light bar moves over the
image and the reflected light falls on a bed of
photosensitive cells. The cells “read” the image,
interpreting it as a series of tiny dots. Each dot
is called a pixel, or picture element. The carriage
scans one line of pixels at a time.
The software converts the values of each pixel into
data that the computer can understand. When the
entire document is scanned, the resulting image
appears on your monitor.
You can print the image as it appears on-screen
or you can manipulate it with image editing or
graphics software to get the results you want.

A W ORD A BOUT S OFTWARE
Your scanner hardware works hand in hand with
your software to produce data files. In fact, the
most important aspect of getting great results with
your scanner is understanding a little bit about the
software that creates these files. The rest of this
booklet presents software topics that will help you
to understand the scanning process. You’ll find
that scanning software is used to produce two types
of files: text files, which contain characters and
letters, or image files, which depict some type of
illustration. Text files can be edited with an
ordinary word processing program. Image files
can be manipulated using special software
programs called image editors.
F ROM P AGE TO F ILE -OCRs C APTURE T EXT
OCR (optical character recognition) programs
decipher hard copy words and covert them into
editable text files, just as if you had typed them
yourself. More powerful programs even recognize
a variety of typestyles and page formats.
Why waste time reentering information to get it on
disk? For businesses with a steady stream of critical
information or any hard copy data that must be
converted to disk, a scanner and an OCR program
can be real time-savers. You can combine infor-
mation from many different sources into com-
prehensive reports, convert old documents to data
files for easy storage, capture information from
trade journals or papers-the list goes on and on.
Even if you usually use your computer for simple
word processing or spreadsheets, you’ll appreciate
the convenience of OCR. To prove it, Epson
includes a leading manufacturer’s OCR Try-Pak
with each of its scanners, so that you can try out

Line art
Line art with shading
OCR for yourself. Scan up to 25 pages with the
Try-Pak. Try it on a fax, have fun with the daily
newspaper, or even that dusty resume you prepared
on the typewriter. If you find you’re hooked, we
offer the full package and documentation at a
considerable discount.
IMAGING PROGRAMS: PICTURE THE RESULTS
You can use imaging programs to capture a wide
variety of artwork, illustrations, and photographs
into image files. Scanned images fall into three
categories: line art, gray scale, and color.
Line art includes all drawings made up of black
and white only, with no gray tones. Both of the
illustrations on the left are examples of line art,
even though the artist has used lines that look like
shading in the second one.
Gray scale (also called monochrome or contin-
uous tone) refers to images such as black and
white photographs that contain various shades of
gray in addition to black and white. You can also
scan a color photograph as gray scale if you
want to print it in black and white.
For color reading, the scanner divides the various
colors in the image into three primary colors: red,
green, and blue. Epson’s powerful 24-bit color
scanners devote 8 bits/pixel to each of the three
colors, so the scanner can represent over 16
million colors.
Use color scanning for color photographs or other
originals which will be printed or presented in color.

R ESOLUTION
Resolution determines how many pixels, or dots,
are used for scanning and reproducing an image.
As the resolution value increases, the scanner
reads and reproduces the image in finer detail.
You might hear resolution described in terms of
dots per inch (dpi), or pixels per inch (ppi).
The best resolution setting really depends on the
type of image you are scanning and the printing
method. The table below shows optimum
scanning resolutions for most needs.
Output Device
Line Art
Gray Scale Color
Black and white 300-400 75
75
printer
Electronic color 300-400 150-200
printer
150-200
Printing press/ 400-800 150-200 150-200
imagesetter
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color photo scanned at 300 dpi requires 25MB!
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resolution that gives acceptable quality keeps file
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sizes manageable.

200 6@/133 line screen
600 dpi/133 line screen
You’ll also notice that if you scan a color image at
600 dpi, the printed result is not much different
from what it is if you scan the same image at 200
dpi, because all printers and printing presses
reproduce the image as a series of dots and have
their own maximum resolution.
Here are two images, one scanned at 200 dpi, one
at 600 dpi, output on the same device. Can you tell
the difference?
An easy way to determine the best resolution for
your intended output is to find out the lines per
inch (lpi) capability of your printer and multiply
it by 1.5. For example, a typical magazine printing
press prints at 133 lines per inch. To tailor your
scanned image for the best possible results
on this press, you multiply the lines per inch
(133) by 1.5:
133 x 1.5 = 199.5
In this example, the resulting number (200) is the
optimum resolution for the scan. (If you regularly
use a service bureau to print your scanned materials,
you can also ask the printer for the lpi of his
particular printing press and to suggest resolutions.)

S ELECTING A P RINTING M ETHOD
Black and white laser printer
Electronic color printer
Printing press
You can print scanned images on a variety of
devices. Here are three of the most common:
Black and white printers (laser, ink jet, or dot
matrix) like those used in most offices produce
good to excellent text and line art but are not
as good for gray-scale images. You might use these
printers to reproduce photographs in newsletters
or informal reports that don’t require the highest
quality. The example to the left shows a typical
photograph printed by a laser printer.
Electronic color printers use laser, ink jet, or other
technologies to produce color or gray scale images
that range in quality from coarsely patterned to
nearly photographic (often called continuous
tone). Electronic color printers work well for
small quantities of color images or for proofs of
images you’ll later print on a printing press. The
image to the left was printed on an electronic
color printer.
Printing presses can produce high quality and
high volume work, You scan and edit your images
and then send the files to a service bureau or
printing company, which uses a high resolution
imagesetter such as the Linotronic
™
300 for high
quality text and gray-scale images. For full-color
images, you scan in color and then use your
image editing software to produce the color
separation files that are necessary for printing
color on a printing press.
Note: All three images on this page were scanned
with an Epson scanner.

W HAT IS I NTERPOLATION ?
Each flatbed scanner has a maximum optical
resolution based on the physical number of light
sensors in the bed. For example, a 400 dpi scanner
has 400 sensors per horizontal inch. Despite
this maximum value, many scanners can use a
process called interpolation to achieve higher
resolutions. Interpolation allows the software to
make an educated guess based on mathematical
probability to determine the value of pixels it can’t
see and then insert these values in the final image.
Interpolation can be especially useful to improve
the jagged appearance in some line drawings, as
shown in the samples on the left.
300 dpi
Epson scanners use interpolation to double
the scanner’s native resolution, so our 300 dpi
scanners achieve apparent resolutions of up to 600
dpi, and our 400 dpi scanners attain resolutions of
up to 800 dpi. By using the enlargement feature,
which goes up to 200% on most programs, you
can even “stretch” the apparent resolution on a
400 dpi scanner to 1600 dpi.
600 dpi, using interpolation

A DJUSTING THE I MAGE
Most scanning software offers a common group of
scanning settings to help you get the results you
want. Many also provide a preview function that
lets you see a sample of what the finished scan will
look like and check the settings. You may have to
experiment a few times to get the results you want,
but you’ll soon be adept at making minor
adjustments to fine-tune your scanned image.
GAMMA AND COLOR CORRECTION
When you scan a color image, you usually want
the tones and colors to be as close to the original
as possible. Two software functions are particularly
helpful for matching your original: gamma
correction and color correction. Gamma
correction lets you adjust the light intensity (or
tone) in the scanned image so that when it is
reproduced-either on your monitor screen or a
printer, the resulting image has similar gradations
to the original. (The term gamma refers to a curve
on a graph that measures the degree of contrast
between light and dark.)
Color correction adjusts the color information so
that the colors in the reproduced image are close
to the original colors. For example, a typical CRT
display uses a combination of red, green, and blue
to produce the entire range of colors. On the other
hand, a color printer usually uses magenta, cyan,
and yellow (and sometimes black) to produce
the same range of colors. The color correction
function processes the image data for the specific
characteristics of the color output device you use,
to produce it.

Gray scale image
Dropout background
E DITING I MAGES TO M AKE Y OUR M ARK
Image editing software lets you manipulate a
scanned image to fit your intended output device,
or to change or repair an image. They work along
the same principle as word processing programs,
letting you delete things, move things around, or
“clean up” a scanned image. For example, you
might want to erase tiny specks or imperfections
that show up in the printout, to repair areas
damaged in the original, or to fill in areas or
broken lines. You can also use image editors
imaginatively to change the final look of your
images, either by eliminating the background,
as shown in the example on the left, or by
combining several scanned images. You can
even change the colors, draw in new details, or
stretch an image to fit your space.
C ONFIGURING Y OUR S YSTEM
FOR G REAT R ESULTS
Adding a scanner to your system requires a bit
of muscle in your other components. When you
plan your system configuration, keep these
questions in mind:
l Do you have enough RAM (Random Access
Memory) in your computer? How much storage
is available on your hard disk? Remember,
scanned images use much more memory than
text files, so you may need to upgrade your
mass storage options or add RAM. You’ll
probably need at least 4MB of RAM and a 40MB
hard disk drive.

l Is computer performance slower than you’d
like? Larger files take longer to process. See if
there is an accelerator board or CPU or RAM
upgrade available for your system.
l Do your video card and monitor support the
resolutions you need to display high quality
scanned images? Check the resolutions
supported by your current video card to make
sure it supports at least 256 colors. Consider
changing the existing video card or adding a
high resolution video or graphics card to boost
performance. For the highest quality you need
a 24-bit card (also called true color).
l If you’ll do most of your printing in the office
on a laser printer, can your printer support the
scanned image? The more complex the image,
the more RAM the printer needs to store
instructions from the computer and compose
complex pages. General purpose lasers are
usually equipped with 512KB of memory
See if memory upgrades are available.
INTERFACES MAKE THE CONNECTION
Epson offers a variety of scanner interface kits
to meet your system requirements. Choose
Bidirectional DOS or SCSI DOS for your
PC-compatible, or Mac SCSI for your Macintosh
®
If you regularly work in both the PC and Mac
environments, consider the Epson ES-800C,
a scanner that supports both the Mac SCSI and
Bidirectional DOS interfaces, so you can share
the scanner between both systems.

A DDING O PTIONS TO Y OUR S CANNER
For the Epson dealer nearest you,
call the Epson Connection at
1-800-922-8911.

EPSON