Colortrac SmartLF large format scanner features
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Colortrac SmartLF Scanner Features
Colortrac SmartLF scanners are compact, lightweight and portable desktop scanners that will fit in any workplace environment. Scanner features include CIS and CCD sensors, transport mechanisms and colour modes & spaces.
Important: Please read Colortrac minimum PC specification for SmartLF Ci, SC and Gx+ scanners.
1-bit, 8-bit greyscale, 16-bit greyscale
When you scan in black & white (mono) or greyscale, Colortrac wide format scanners scan in 16-bit greyscale. This means that they capture over 65,000 shades of gray.
The 65,000 shades of gray are then reduced down to two to create a black and white image (called 1-bit) or to 256 to create an 8-bit greyscale.
Scanning in 16-bit greyscale then
reducing to 8-bit greyscale improves shadow and highlight detail in 8-bit
greyscale images.
8-bit colour, 24-bit colour, 48-bit colour
When you scan in colour, Colortrac wide format scanners scan in 48-bit colour. This means that they capture trillions of colours.
These trillions of colours are then reduced down to "the best" 16.7 million colours to create a 24-bit colour image, or to 256 colours to create an 8-bit colour image.
Scanning in 48-bit colour then reducing to 24-bit colour or 8-bit colour enhances the colour fidelity of 24-bit colour and 8-bit colour images and improves shadow and highlight detail.
APT is the transport system used to feed documents through Colortrac SmartLF Cx and Gx+ scanners. APT maintains pressure on the document as it travels through the scanner without introducing friction. This:
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Preserves delicate originals by using minimum necessary force.
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Prevents documents from getting trapped.
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Reduces shadows and retains focus by smoothing folds and wrinkles and keeping documents flat against the scan glass.
2+4 all-wheel-drive Active Paper Transport
Colortrac SmartLF Cx+ 40 large format scanners use 2+4 all-wheel-drive Active Paper Transport. The document is fed into the scanner from the front over a gently curved feed tray, is detected by optical sensors and is automatically loaded.
The document is then transported between precision ground drive rollers with high grip rubber tires, ensuring optimum support and accurate positioning as it enters the scan window.
Finally, it engages with two belt driven hold-down rollers positioned over the two rows of CIS imaging arrays. The hold-down rollers auto adjust to media thickness while maintaining constant pressure and contact on the scan glass.
Advanced 2+3 all-wheel-drive Active Paper Transport
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Colortrac SmartLF Gx+ 28, 42 and 56 large format scanners use Advanced 2+3 all-wheel-drive Active Paper Transport.
This is the same as 2+4 all-wheel-drive APT, except that it only employs a single hold-down roller - in Gx+ wide format scanners all the CCDs are in a single row, so only one hold-down roller is necessary.
Advanced single roller paper transport (ASPRT)
ASRPT is the transport system used to feed documents through Colortrac SmartLFCi 24 and Ci 40 wide format scanners. ASRPT maintains pressure on the document as it travels through the scanner without introducing friction. This:
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Preserves delicate originals by using minimum necessary force.
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Prevents documents from getting trapped.
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Reduces shadows and retains focus by smoothing folds and wrinkles and keeping documents flat against the scan glass.
The document is fed into the scanner from the front over a gently curved feed tray, is detected by optical sensors and is automatically loaded. The document is then transported between a single large precision ground solid roller and a flexible media guide mechanism.
The media guide mechanism contains small rollers supported by springs, that dynamically adjust themselves to the thickness of the media being scanned and hold it lightly but firmly between the transport roller and the CIS sensors.
The document passes around the roller and is fed out of the front of the scanner.
The Ci range's front exit path is unique among today's wide format scanners. Not only does it make it easier to retrieve documents from the scanner after scanning, but it saves time and document wear over large format scanners that employ a "rewind to front" method for getting documents to exit at the front after scanning.
In addition, the Ci range is the only large format scanner available today that uses single roller transport. This makes it Colortrac's most accurate large format scanner to date. Rollers can only be machined to a certain uniformity tolerance, whatever their size. One large, slowly revolving roller introduces less error than multiple rollers that must complete many revolutions per scan.
SingleSensor (patent pending) digital imaging technology is a Colortrac invention that combines CIS elements in a single line array. It offers true 1200dpi optical resolution.
SmartLF Ci 24 & Ci 40
Most CIS wide format scanners have one set of LEDs positioned at one end of each
CIS sensor. These LEDs are shone down a single light guide to provide
illumination. In the Colortrac SmartLF Ci 24 and Ci 40 large format
scanners, each CIS sensor has two sets of LEDs, one at each end. These are shone
down two light guides. Because illumination is bi-directional instead of uni-directional
there is less potential for shadowing.
SmartLF Gx+ 28, 42 & 56
Most CCD wide format scanners are illuminated by fluorescent tubes. Colortrac
SmartLF Gx+ 28, 42 and 56 large format scanners are illuminated by white LEDs
which are shone from either side of the CCD cameras.
Large format scanners use one of two imaging systems – Contact Image Sensor (CIS) or Charge Coupled Device (CCD).
A CIS is an integrated module that comprises an illumination system, an optical system and a light-sensing system - all within a single compact component.
A CIS senses light that is incident on its silicon surface which is divided into square cells. The size of each cell on the silicon surface is the same as the size of the information being captured (e.g. in a 600 dpi scanner each cell is 1/600" across) and information is captured at 1:1. As no reduction or enlargement is required, the distance between the document being scanned and the sensor is very short (~13 mm - hence contact image sensor).
The optical system is a rod lens array that directs light from the document surface onto the silicon surface. Because the optical path is short and simple, quality CIS wide format scanners cost less to manufacture than quality CCD scanners, are lighter and more compact, robust and portable and require little or no calibration.
Illumination is provided by one or two sets of Light Emitting Diodes (LEDs) shining down a light guide or guides, which in turn direct the light onto the document. There are three LEDs (red, green, blue) in each set. These are either strobed rapidly to provide colour content in the scan or shone simultaneously to provide a perfectly registered black and white scan.
Because LEDs require no warm up time (unlike fluorescent tube illumination), CIS wide format scanners can be used as soon as they are turned on and can be turned off when not in use. LEDs also require less power than fluorescent tubes, only come on while a scan is being made, last indefinitely (no consumables) and are environmentally friendly - LEDs contain recyclable components and are mercury free.
However, red, green, blue LEDs cannot provide as wide a colour gamut or dynamic range as white fluorescent tubes or white LEDs with colour filters used in CCD large format scanners. This means that CIS large format scanners are unsuitable for photographic material or documents where colour integrity and shadow detail is important.
The sharpness of scans created by CIS wide format scanners makes them ideally suited to scanning the small details and fine lines found in technical documents, where exact colour fidelity is not required.
Colortrac SmartLF Cx+ 40, Ci 24 and Ci 40 wide format scanners use CIS imaging systems.
Large format scanners use one of two imaging systems –Charge Coupled Device (CCD) or Contact Image Sensor (CIS).
Wide format scanners contain one or more CCDs each sensing light that is incident on its silicon surface. This surface is divided into square cells, each several micrometres across (e.g. 5.25 µm). In a colour wide format scanner, each CCD has three closely-spaced parallel lines of cells, each line being overlaid by a different colour filter (red, green, blue). Some colour CCD large format scanners including Colortrac SmartLF CCD scanners have four lines of cells (quadri-linear CCDs). In this case the fourth line has no filter and is used for monochrome scanning - called panchromatic monochrome.
Now consider the geometric requirements for a CCD wide format scanner. To produce a scanner with 600 dpi optical resolution, the scanner manufacturer needs to design an optical system which focuses light from a 1/600" square pixel at the document (0.04233 mm) onto a 5.25 µm (0.00525 mm) square cell at the CCD silicon surface - a reduction of approximately 8:1. This is done using photographic enlarger lenses and, usually, mirrors to fold the optical path, which can be up to a meter or more in length, into a small space.
This long optical pathway with its sensitive components means that quality CCD large format scanners cost more to manufacture than quality CIS large format scanners, tend to be heavier (they need to be built with more rigidity) and less compact and potentially require more calibration.
The use of lenses and mirrors also introduces some geometric distortion. The parts of a scan most likely to suffer geometric distortion are those at the edge of a CCD's range. Colortrac use multiple CCDs across the scan width of their CCD large format scanners. This avoids the need to work to the edge of the lens, thus minimizing distortion.
The manufacturer of a CCD wide format scanner must also design an illumination system, traditionally using one or two fluorescent tubes. This white light is combined with the colour filters within the CCD to determine the colours produced by the scanner. Although the colour filters within the CCD are controlled by the CCD manufacturer, the scanner manufacturer is able to control the illumination system and is able to apply proprietary processing to the CCD output to optimize the scanner's colour performance.
This allows CCD wide format scanners to capture a wider gamut and dynamic range than CIS scanners and makes CCD scanners more suitable for photographic material or documents where colour integrity and shadow detail is important.
However, while traditional CCD scanners with fluorescent lighting have superior colour imaging, they have a number of disadvantages.
While a fluorescently lit scanner can be used within five minutes of switching on, you need to let it warm up for about an hour in order for the tubes to reach their optimum light intensity and for the tube temperature to reach equilibrium. If you do not do this, colour and stitch inaccuracies may result. Because of this warm up time, it is impractical to turn the scanner off when it is not in use during the day. This means that fluorescently lit scanners consume more power than they need.
Fluorescent tubes normally need replacing every year or two so they are deemed consumable parts. And, because the characteristics of the tubes change as they age, fluorescently lit scanners require relatively frequent calibration. Also, the tubes contain mercury so they cannot be disposed of in an environmentally friendly manner when they die.
Colortrac's SmartLF Gx+ 28, 42 and 56 large format scanners are CCD scanners, but instead of using traditional fluorescent tubes they use white LEDs.
White LEDs give the Gx+ family all the benefits of CCD technology but without the downsides. Because LEDs do not need warm up time, Gx+ wide format scanners can be used as soon as they are turned on and can be turned off when not in use. LEDs also require less power than fluorescent tubes, only come on while a scan is being made, last indefinitely and are environmentally friendly - LEDs contain recyclable components and are mercury free. White LED illumination has enabled Gx+ large format scanners to become ENERGY STAR® qualified.
Closed loop calibration is a method of colour calibrating a printer in conjunction with the scanner it is going to be used with, to ensure that scanned and printed colours match the colours on the original scanned document.
First, a standard colour chart is output to the printer. This printed colour chart is then scanned along with a supplied standard colour chart. The scans of the printed colour chart and the standard colour chart are then compared to known colours and this information is used to build ICC / ICM profiles of the printer and scanner colour characteristics.
These profiles are then used to ensure accurate colour across the scanner - printer system for subsequent scan-to-print operations.
SmartWorks Pro Copier software includes a user-friendly Calibration Wizard for closed loop calibration
A colour space is simply a range of colours.
Colortrac SmartLF Cx+ 40 wide format scanners use a RAW RGB (un-processed RGB) colour space. They do not conform to a standard colour space but simply store colours as scanned.
Colortrac SmartLF Ci 24, Ci 40, Gx+ 28, Gx+ 42 and Gx+ 56 large format scanners can either use RAW RGB or conform to a standard colour space called sRGB. When a scan is made the colours are converted to the closest sRGB equivalent. The advantage of conforming to a standard colour space is that it improves the user's perception of the scanner's colour accuracy. However, it may narrow the scanner's gamut.
Dynamic normalisation application (DNA)
DNA is part of the utility software included with every Colortrac SmartLF large format scanner.
In common with virtually all other large format scanners, SmartLF wide format scanners use three or more CCDs / CIS sensors to capture large format scans. From a manufacturing standpoint it is impossible to guarantee that the colour characteristics of every sensor will be exactly the same or that they will be totally free from slightly different temperature gradients once installed inside the scanner.
DNA measures any unevenness in a scan caused by these internal discrepancies so that it can be compensated for in subsequent scans. It also analyzes and sets appropriate dark and light levels.
This ensures that scans are uniform and free of colour casts, and maximizes shadow and highlight detail.
Dynamic range is the amount of detail a scanner can see in dark areas before "blacking out", or in light areas without "whiting out".
Gamut is the range of colours a scanner can capture.
ICC (or ICM) profiles describe the colour characteristics of scanners, printers, monitors etc. The profiles are used in a colour management system to ensure that printed and / or viewed colours match the colours on the original scanned document. ICC and ICM profiles are the same, but the profiles have different file extensions.
SmartWorks Pro Scan software allows externally created ICC profiles to be embedded into any scan so that when the file is displayed on an appropriate viewer or printed its colour will be correctly interpreted according to the profile.
SmartWorks Pro Copier software has a built in Calibration Wizard that produces ICC profiles for the scanner, monitor and any attached printer.
Motorised thick media adjusts the scanner to accept extra thick media such as mounted images on Foamex and Kappa board, extending the maximum media thickness that Gx+ wide format scanners can accept from 2mm to 20mm.
MTM is implemented in the T (Thick) versions of Colortrac SmartLF Gx+ 28, Gx+ 42 and Gx+ 56 large format scanners.
A raster image processor is a software program that manages the output of scans and other files to a printer. The RIP processes (rips) the files in such a way that they can be printed more quickly and at a higher quality than using standard Windows printer drivers. RIPs normally include facilities for queuing print jobs, batch processing and printing reprints.
Thresholding is a level applied to greyscale data to separate interesting data (black) from the background (white).
IAT (Intelligent Adaptive Thresholding) is a more advanced thresholding type where the level to separate black from white is continually altered in response to the background darkness. Consider the discoloured drawing below:
If it is scanned using simple thresholding, some of the detail is lost (above, left). However, if it is scanned using IAT, the detail becomes visible (above, right).
SmartWorks EZ software, included with every Colortrac SmartLF large format scanner, has three IAT settings. SmartWorks Pro software, a cost option, has comprehensive IAT where you can make changes in real time on the screen by adjusting two slider bars.
IAT makes it quick and easy to create high quality scans from poor quality originals.
Please read the PC minimum specification for Cx, Ci and Gx+
scanners - Colortrac PC system requirements.
