Contex SD 3600 series, Technical Service Manual

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C-7
Appendix - C --- Scanner Terms
Screen Calibration
A program that helps adjust the computer screen
to get the best display of scanned pictures and
documents. This program is run during installation
and should be used again any time that the com-
puter screen or the lighting around the computer is
changed.
SCSI (Small Computer System Interface)
An interface that allows hard disks and other high-
performance peripherals to be attached to Macin-
tosh and PC computer systems.
SCSI Card
The printed circuit card that came with the scan-
ner. With its driver software, the card allows the
computer to talk to the scanner. The card is ASPI
compatible with a SCSI-II output connector.
SCSI
Small Computer System Interface. Specification of
interface to computer equipment like disks, print-
ers, scanners etc.
Shadow Detail
The amount of detail contained in the dark parts of
an image. It is desirable to maintain shadow detail,
but there is a risk of decreasing overall contrast if
one lightens the shadow too much in an attempt
to expose additional detail. If an image is scanned
without shadow detail, it will be impossible to re-
gain detail using an image editing program.
Shadow
The darkest part of a picture; reproduced as black
onscreen or when printed.
Sharpness
An attribute of a scanned image and also an at-
tribute of scanner quality.
SRGB
Hewlett-Packard and Microsoft proposed the addi-
tion of support for a standard color space, sRGB,
within the Microsoft operating systems, HP prod-
ucts, the Internet, and all other interested vendors.
The aim of this color space is to complement the
current color management strategies by enabling
a third method of handling color in the operat-
ing systems, device drivers and the Internet that
utilizes a simple and robust device independent
color definition. This is to provide good quality and
backward compatibility with minimum transmission
and system overhead. Based on a calibrated colori-
metric RGB color space well suited to Cathode Ray
Tube (CRT) monitors, television, scanners, digital
cameras, and printing systems, such a space can
be supported with minimum cost to software and
hardware vendors.
Stitching
In large format multiple CCD camera scanners,
electronic stitching adjusts for overlap in the field
of view of adjacent cameras. Automatic stitching at
start of scan ensures that each camera captures
the correct number of pixels independently of me-
chanical and thermal changes.
Subtractive Colors
The subtractive primary colors: cyan, magenta, yel-
low. As ink applied to a piece of paper by a printer,
these colors absorb light and alter the colors seen
by looking at the printed paper. Cyan ink absorbs
the red third of the spectrum, magenta ink absorbs
the green third, and yellow ink absorbs the blue
third. This should theoretically cause the viewer to
see a black color, but due to unavoidable impuri-
ties in the inks, there is still light reflected and the
viewer sees a muddy brown. The absence of CMY
pigments results in white.
TIFF
Tagged Image File Format. One of the most com-
mon graphic file formats for line-art and photo -
graphic images.
Tonal Distribution
Tonal Distribution describes the distribution of vari-
ous bright or dark tones within an image. During
the scanning or image editing stage, tones can be
redistributed, lightening a dark image or darkening
a light one.
Tone Compression
A term used in scanning and image editing that
refers to compressing the broad range of tones
and colors in an image down to the narrower range
available on a printer.
Tone Curves
The shape of the tone transfer curves can be ad-
justed by the user to alter color or tone correction.
The lower left end of the curve typically represents
the dark portions of a picture and an upward bend
will typically lighten the shadows. Similar capabili-
ties exist by working with the middle or highlight
parts of the curve. In this way it is possible to alter
only certain tonal ranges of an image without mak-
ing un-wanted changes to other parts of the image.
Tone
Any color or neutral that is denser than white.
True color
True color systems provide eight bits for each of
the three components (red, green and blue). There-
fore true color is often referred to as 24-bit color.
TWAIN
A standard method of communications that pro-
grams can use to send instructions to hardware
(such as scanners) and receive data back from
them (such as pictures).
UCR
Under Color Removal. A color separation setting
used on color photographs where cyan, magenta
and yellow inks are removed from dark, neutral
areas and substituted by black ink. The advantages
are a reduction in overall ink usage. See also
GCR.