Hermes VANGUARD OPTIMA, User Manual

Page: 33 / 113

3-8 The Printer Driver
Dither Type
Specifies the type of dithering used in printing non-black and white bitmaps and multicolored
clipart images. Since the laser system is really acts like a black and white printer (laser ON is
considered black and laser OFF is considered white), grayscale or color photographs(bitmaps),
as well as multicolored clipart images get turned into dithered images when reproduced by the
laser system. This process is very similar to how newspaper photographs as well as laser
printer photographs are printed.
Choose “
Halftone ” if you want the images to print with a halftone screen that has a preset
pattern that is based on the “Resolution” selection located in the “Laser Settings” tab in the
driver. The chart below describes that screen angle, shape, and lines per inch pattern applied
for the different DPI resolution choices in the driver. These are fixed patterns that cannot be
altered.
RESOLUTION ANGLE SHAPE LINES PER INCH
1000 45 DEGREES ROUND 180
500 45 DEGREES ROUND 90
333 45 DEGREES ROUND 60
250 45 DEGREES ROUND 45
200 45 DEGREES ROUND 36
Choose “
Error Diffusion ” if you would like the black and white pixels to be scattered in a
random pattern to represent shading. This randomized dither pattern is unlike the fixed pattern
of a “Halftone” screen and can be adjusted.
Error Diffusion Controls
When you select “Error Diffusion” this section becomes enabled allowing you to adjust 3
settings: Brightness, Contrast, and Diffusion.
“
Brightness ” is similar to the brightness control in most photo editing software. Adjusting the
slider to the “Bright” side brightens each pixel in the bitmap one shade of gray for each
increment. Adjusting the slider to the “Dark” side darkens each pixel in the bitmap one shade of
gray for each decrement.
“
Contrast ” is also similar to the contrast control in most photo editing software. Adjusting the
slider to the “High” side increases the contrast of the image by making the lighter colors brighter
and the darker colors darker which decreases the amount of gray colors. Sliding it to the “Low”
side decreases the contrast of the image by making the lighter colors darker and the darker
colors lighter which increases the amount of gray colors.
“
Diffusion ” controls the amount of graininess or “noise” level. Adjusting the slider to the
“Heavy” side increases the noise level thus causing the image to appear more “noisy”. Sliding it
to the “Light” side reduces the noise level and causes the image to appear more solid and have
less “noise”.