Xante Accel-a-Writer 812 User manual

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Chapter 7 - Advanced
Imaging
Chapter Overview
Levels of Gray
Line Screens
Scanner Resolutions
Line Art Scanning
Halftone Scanning
TIFF, PICT, EPS Formats
Gamma Corrections
Enhanced Screening
Accurate Calibration Technology
Page Design
Typefaces and Fonts
Typeface Forms
Other Elements of Design
Orientation
Pitch
Point Size and x-Height
Spacing
Page Design Tips

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Notes

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( )2+1
Introduction
To take full advantage of your Accel-a-Writer 812’s high resolution
and make your images look their best, it is important that you
understand levels of gray, line screens, scanner resolutions, and their
uses within specific applications.
The first half of this chapter explains what levels of gray and line
screens are and how to work with them to achieve the best possible
quality of output. It also covers scanning, selecting formats for your
files, and using gamma corrections, enhanced screening, and
XANTÉ Accurate Calibration Technology. The second half covers
terms and elements of page design with tips for adding finishing
touches for a truly professional image.
Levels of Gray
The resolution of a laser printer is measured in dots per inch (dpi).
The resolutions on your Accel-a-Writer 812 are 600 x 600 dpi and
1200 x 1200 dpi.
Generally speaking, the human eye can detect approximately 200
shades of gray in an image. This means that the higher the levels of
gray (number of shades) used to produce a halftone image, the
smoother the image looks during the transition of changing dot sizes.
The following simple formula can help you determine the shades of
gray used to produce an image:
dots per inch
lines per inch
For example, if you print at 600 x 600 dpi with a 75 line screen, the
image produced has 65 levels of gray (600/75 = 8; 8 x 8 + 1 = 65). If
you want more levels of gray at 600 dpi, the line screen or lines per
inch (lpi) has to be reduced.

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Keep in mind that the higher the lines per inch, the tighter the screen
on the image will be. To produce higher levels of gray without using
a lower line screen, you must print at a higher dpi. An illustration of
this would be to print the same image at the Accel-a-Writer 812’s
1200 x 1200 dpi with the same 75 line screen. You would now have
approximately 256 levels of gray (1200/75=16; 16 x 16 + 1 = 257).
Use the following table as a guide when working with levels of gray.
LPI ToAchieve 256 Levels of Gray
Printer
Resolution LPI
1200 x 1200 dpi 75
600 x 600 dpi 38
Line Screens
Knowing how many levels of gray you would like to achieve is one
factor in determining the appropriate line screen to use. Depending
on the individual image quality, some degree of experimentation
usually is necessary to produce the best possible output. You do not
always have to achieve 256 levels of gray for the best output. We
have found the following line screens (lpi) to work the best: 60 for
600 dpi and 95 for 1200 dpi. Trying these line screens generally
gives you a more precise idea of the optimum output for a particular
image.
Note: Your Accel-a-Writer 812 features XANTÉ’s new enhanced
screening technology which lets you select different gray
level and gamma correction combinations to further fine tune
the quality of your output. See “Gamma Corrections” and
“Enhanced Screening” later in this chapter for more details.

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Scanner Resolutions
Another way to insure high quality output for your images is to
determine the optimum scanning resolution.
Line Art Scanning
For line art, the optimum scanning resolution would be at the same
resolution as the output device, especially when reproduced at the
same size. For example, when printing from your Accel-a-Writer 812
in the 600 x 600 dpi mode, the scanner resolution should be set at
600 x 600 dpi.
Halftone Scanning
The resolution for scanning a halftone is usually lower than that of
the output resolution. Black and white images should generally be
scanned at a resolution of 2 times that of the line screen used, if
printing at 100% size. For example, if a line screen of 95 is used, the
scanner resolution should be set to 190 dpi (95 x 2). If that resolution
cannot be selected, choose the next higher resolution available. Also,
scanner resolutions depend on the size at which the output is printed.
If the previous example were to be printed at 75% of original size,
then the scanner resolution should be set to 142 dpi (95 x 2 x .75).
The formulas for scanning in this section are used to determine the
optimum resolution possible. Scanning the image at a lower than
optimum resolution results in less detail. Scanning at a higher
resolution increases the file size and the processing time, and it may
only slightly increase the amount of detail. The following is a
formula for scan resolution.
desired lpi x 2 x % of original size

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TIFF, PICT, EPS Formats
After scanning the image, you need to decide the format in which to
save it. The three most popular formats are TIFF (Tagged Image File
Format), PICT (from Picture), and EPS (Encapsulated PostScript)
files. If you use a scanning application such as Photoshop, make sure
to choose the appropriate line screen under Page Setup before saving
the image. This is essential for importing the image into other
applications. Some programs do not allow you to change the line
screen of an individual PICT or EPS image once it is imported.
PageMaker only allows you to change the line screen of a TIFF file.
Do this by clicking the image and choosing Image Control under the
Elements menu. Set the line screen using the formulas in the
previous section, “Halftone Scanning.”
Note: Different versions of PageMaker may work differently. See
the application manual for details.
QuarkXPress only allows you to change the line screen of an
individual TIFF file. Do this through the Style menu. QuarkXPress
gives you a choice of Normal (default), 60, 30, 20 and Other line
screens. You may choose your own lpi through Other. QuarkXPress
goes a step further by allowing you to change the line screen of the
entire document in Page Setup under the File menu.
Note: Different versions of QuarkXPress may work differently.
See the application manual for details.
For more information on specific applications, see appendix B,
“Application Notes.”
Gamma Corrections
XANTÉ Halftone Calibration Technology provides a sophisticated
gamma correction feature. This feature allows you to change
midrange contrasts by adjusting gray-scale values without altering
the black shadow and white highlight values at each end of the scale.

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For example, if a scanned image is too dark, you can use the printer’s
front panel or use the software printer setup to select a new gamma
setting to lighten and enhance the details. Gamma correction brings
out details that can be lost when printing at higher line screens or
when dark photos are scanned.
Your Accel-a-Writer 812 offers seven gamma settings, 0 through 6
with 0 as the default. Settings 0 through 5 progressively lighten the
midrange values. If you need a negative (reverse) image, which is
required by some printing processes, you can create one using
gamma 6 rather than using a software application. Figures 7.1 and
7.2 illustrate the effects of gamma correction settings. Chapter 5,
“Configuration,” contains details on where to find the gamma
options in the menu structure and how to make the selections.
1
10
Output Levels
Gamma 0
Black White
Input Levels
Black White
Fig. 7.1 Gamma Correction 0

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1
10
Output Levels
Black White
Input Levels
Gamma 6
Black White
1
10
Output Levels
Black White
Input Levels
Gamma 5
Black White
1
10
Output Levels
Black White
Input Levels
Gamma 4
Black White
1
10
Output Levels
Black White
Input Levels
Gamma 3
Black White
1
10
Output Levels
Black White
Input Levels
Gamma 2
Black White
1
10
Output Levels
Black White
Input Levels
Gamma 1
Black White
Fig. 7.2 Gamma Corrections 1 through 6

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If you use gamma corrections in combination with XANTÉ’s new
enhanced screening technology, you can further fine tune your
output quality. See “Levels of Gray” earlier in this chapter and the
next section, “Enhanced Screening,” for more details.
Enhanced Screening
XANTÉ’s enhanced screening allows you to select from the normal
(default) or the enhanced screens defined by 145, 197, or 256 levels
of gray using either the printer’s front panel or via software printer
setup. If you use the front panel, the default enhanced screen is setup
under the MISC:SCREEN menus. If you use the software printer
setup, you can select the levels of gray and gamma settings
simultaneously. Gray level and line screen combinations of enhanced
screens are defined as:
Levels Line Screens
of Gray 600 dpi 1200 dpi
145 70 140
197 60 120
256 53 106
There are nineteen possible gamma correction and levels of gray
combinations from which you can choose to fine tune your output
quality. Depending on your printing environment, Macintosh or PC,
use one of the following procedures to select the enhanced screens.
In a Macintosh environment, use the following procedure to select
the enhanced screens.
1. Select Print… from the File menu from within your
application. The print dialog box appears.

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2. Click Options…. The Options window appears
3. Select the desired screen.
4. Click OK. The print dialog box reappears.
5. Click Print.
In a PC environment, use the following procedure to select the
enhanced screens.
1. Start your Windows application.
2. Go to the Control Panel and select Printers.
3. Click Setup….
4. Click Features….
5. Locate the Enhanced Screen options and select the desired
screen.
6. Click OK.
7. Click OK.
8. Close the Control Panel window.
Accurate Calibration Technology
XANTÉ’s Accurate Calibration Technology (X•ACT) allows you
easily to calibrate the printer’s engine to print more precise
horizontal and vertical dimensions within the width of one dot.
X•ACT compensates for print engine variations. Every printer prints
in a slightly different way; one engine may print one line a little long
and another a bit short with a usual accuracy of 1 mm ±2 mm. While
this variance is acceptable for many uses, it is unacceptable for color
separations and other jobs where pinpoint accuracy is essential.

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Working with X•ACT varies depending on if you are in a PC or
Macintosh environment. Also, after you adjust the printer’s line
length, you need to adjust the printer’s margin setting accordingly.
Both adjustments can be done using XANTÉ’s Command Center.
In a Macintosh environment, use the following procedure to calibrate
line lengths and adjust the printer margins.
1. Start Command Center by double clicking its icon.
2. Select X•ACT Calibration… from the General menu. The
following screen appears.
Fig. 7.3 X•ACT Screen
3. Select the media size you are using in the Paper Size box(fig.
7.3).
4. Click Update/Print. A page prints with a horizontal and a
vertical line on it.

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5. Measure the horizontal line. If it is shorter or longer than the
measurement shown underneath the horizontal scroll bar in
figure 7.3, adjust the scroll bar until the measurement reads the
exact length of your line.
6. Measure the vertical line. If it is shorter or longer than the
measurement above the vertical scroll bar in figure 7.3, adjust the
scroll bar until the measurement reads the exact length of your
line.
7. Click Update/Print. When the new page prints, measure the
lines. They should be the correct lengths. If not, repeat steps 5,
6, and 7 until they are correct.
8. Click Close when both lines are the correct length. You return
to Command Center’s main screen.
9. Select Margin Adjustment… from the Printers menu. The
following screen appears.
Fig. 7.4 Align Printer Margins

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10. Click Set & Print. An alignment test page prints giving current
printer settings at the bottom.
11. Measure where the x and y axes cross. They should cross 1" up
from the bottom and 1" over from the left side of the page. If
the lines cross at the correct place, skip to step 15.
12. Check the measurements from step 11 and then use the x scroll
bar to make x axis changes and the y scroll bar to make the y
axis changes (fig. 7.4). For example, if the x axis is low, move
the x scroll bar right until you reach the desired number of
units.
13. Click Set & Print. An alignment page with new settings prints.
14. Measure where the x and y axes cross. If positioning is correct,
skip to step 15; if not, repeat steps 11 through 14 until the lines
cross 1" from the bottom and 1" in from the left side of the
page.
15. Click Close. Then, select Quit from the File menu to exit
Command Center.
In a PC environment, to calibrate line lengths and adjust printer
margins.
1. Start Command Center by double clicking its icon.
2. Select Product… from the Controller menu. A screen appears
listing the available printers.
3. Select your printer from the list and then click OK.

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4. Select X•ACT… from the Controller menu. The following
screen appears.
Fig. 7.5 The X•ACT Screen
5. Select the media size you are using from the Paper menu (Fig.
7.5).
6. Click Update/Print. A page prints with a horizontal and a
vertical line on it.
7. Measure the horizontal line. If it is shorter or longer than the
measurement to the right of the horizontal scroll bar (fig. 7.5),
adjust that bar until the measurement reads the exact line
length.
8. Measure the vertical line. If it is shorter or longer than the
measurement above the vertical scroll bar in figure 7.5, adjust
that scroll bar until the measurement reads the exact length of
the line.
9. Click Close when the horizontal and vertical line settings
match the lengths of their respective lines. You return to
Command Center’s main screen.

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10. Select Align Paper… from the Controller menu. The following
screen appears.
Fig. 7.6 Align Printer Margins
11. Click Print Test. An alignment test page prints giving current
printer settings at the bottom.
12. Measure where the x and y axes cross. They should cross 1" up
from the bottom and 1" over from the left side of the page. If
the lines cross at the correct place, skip to step 16.
13. Use the x scroll bar to make x axis changes and the y scroll bar
to make y axis changes (fig. 7.6). For example, if the x axis is
low, move the x scroll bar to the right the desired number of
units.
14. Click Reset Margins and then click Print Test. An alignment
page prints with the new settings.
15. Measure where the x and y axes cross. If the positioning is
correct, skip to step 16; if not, repeat steps 14 through 17 until
the x axis is correct.

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16. Click Close when both axes are correct. Then, select Quit from
the File menu to exit Command Center.
Page Design
Advanced imaging includes not only the mechanical side of printing,
but also the elements of page design. Your Accel-a-Writer 812 with
true Adobe PostScript takes care of most of the mechanical side,
allowing you such freedom as scaling, rotating, and filling text and
graphics. However, a basic understanding of terms and elements of
page design can help you add finishing touches for a truly
professional image.
The rest of this chapter deals with some of the language and
elements used in desktop publishing page design.
Typefaces and Fonts
Two very important terms to understand are typefaces and fonts.
These terms often are used interchangeably which can lead to
confusion sometimes. A font is actually a subdivision of a typeface.
Typeface refers to the style of printing type, not the size. The style
includes design elements such as spacing, stroke, and weight which
are covered later in this chapter.
A font is one size of a typeface and includes all the available
characters of that typeface.
Serif, Sans Serif, and Miscellaneous Typefaces
Typefaces fall into three categories of styles, serif, sans serif, and
miscellaneous. A serif is an extra flourish or decoration added to the
end of a main line forming a letter, character, or symbol.

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PostScript PostScript
Serif (Times Roman) Sans Serif (Helvetica)
Fig. 7.7 Serif and Sans Serif Typefaces
Serif typefaces include extra flourishes such as the small circle at
the top of the a or the small tails hanging down each end of the cross
bar in the T in Times Roman (fig. 7.7).
Sans Serif typefaces lack the decorations. Sans means without, and
these kinds of typefaces have very clean, plain lines such as those
found in the Helvetica typeface (fig. 7.7).
Miscellaneous typefaces include those which have combinations of
serif and sans serif designs as well as graphic type characters such as
arrows, hearts, squares, or Greek symbols.
Each typeface category lends itself to particular areas of page design.
For example, the small detailed lines on a serif typeface helps draw a
reader’s eye across a line of text. This makes it well suited for body
text such as the Times Roman font used in this manual.
The clean, sharp lines of a sans serif typeface make it excellent for
short headlines or signs. The lack of detail, makes it easier for the
eye to group several words into a short phrase, grasping the meaning
at a glance. However, it lacks the drawing effect of details which
make long text blocks easier to read.
Miscellaneous typefaces are handy to draw attention to a particular
section of the page or indicate breaks in topics or sections. For
example, three diamonds ( ◊◊◊) signal the ends of major chapters
in this manual.
Your Accel-a-Writer 812’s PostScript typefaces feature all three
categories: serif, sans serif, and miscellaneous.

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Serif Sans Serif
Courier Helvetica
Courier-Bold Helvetica-Bold
Courier-BoldOblique Helvetica-BoldOblique
Courier-Oblique Helvetica-Oblique
ITC Bookman-Demi Helvetica-Narrow
ITC Bookman-DemiItalic Helvetica-Narrow-Bold
ITC Bookman-Light Helvetica-Narrow-BoldOblique
ITC Bookman-LightItalic Helvetica-Narrow-Oblique
NewCenturySchlbk-Bold ITC AvanteGarde-Book
NewCenturySchlbk-BoldItalic ITC AvanteGarde-BookOblique
NewCenturySchlbk-Italic ITC AvanteGarde-Demi
NewCenturySchlbk-Roman ITC AvanteGarde-DemiOblique
Palatino-Bold
Palatino-BoldItalic Miscellaneous
Palatino-Italic Symbol (Σψµβολ)
Palatino-Roman ZapfDingbats (✺❁❐❆✤❉■❇❂❁▼▲)
Times-Bold
Times-BoldItalic
Times-Italic
Times-Roman
ITC ZapfChancery-MediumItalic
Typeface Forms
Typefaces can be broken down into various forms to help distinguish
them. These forms include italic, oblique, bold, demi, medium, light,
and narrow. The forms can be used separately or in combination to
add to the impact of the printed copy. (See the typeface sample in the
previous section.)
Italic and oblique forms are the printed versions of hand written
(cursive) copy. Although the letters do not touch, their slant gives the
impression of being written in long hand. Italic forms are designed
individually, while oblique are mechanically slanted forms of the
original typeface.

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Bold, demi, medium, and light forms are created by varying the
stroke weight (density) of character lines. For example, the following
note has a bold italic introduction to draw attention, but the body text
switches back to a medium weight (sometimes referred to as roman)
format for easy readability.
Note: Although forms may be combined such as bold italic
versions, if you change form too often within a document,
the forms tend to lose the power to draw attention and end
up with a cluttered appearance.
Other Elements of Design
Other elements of design besides typeface forms include orientation,
pitch, point size, and spacing.
Orientation
The terms portrait and landscape orientations come from the art
world and indicate the direction of a picture or copy on the page.
Usually portraits are narrow in width and long in length while
landscapes are wider across and shorter in length. The same is true
when you print from your Accel-a-Writer 812. Copy across the
narrow direction of the page is in portrait orientation which is used
for most business letters. Landscape orientation goes across the wide
dimension of the page and is used often for spreadsheets and graphs.
Portrait Landscape
Fig. 7.8 Page Orientations

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Pitch
Pitch, sometimes referred to as cpi or characters per inch, indicates
the number of characters which can fit horizontally within one inch.
For example, your printer has the PCL typeface Courier 10 pitch, 12
points. Ten characters fit within an inch and the size is 12 points in
height.
123
This is 10 characters/inch pitch
This is 12 characters/inch pitch
This is 15 characters/inch pitch
Fig. 7.9 Pitch Samples