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Colortrac SmartLF Cx 40 review

This is an edited version of an article written by Steve Hannath of Softcover for publication in the March/April 2006 issue of CAD User (UK).

In mid-2004 Colortrac Limited, a British company based in St Ives, near Cambridge, gave cost-conscious CAD users and AEC professionals something to cheer about. Large format scanner prices, long resistant to change, were shattered by Colortrac's SmartLF 4080c, “the first A0 colour scanner in the UK to break the £5000 barrier”. (Smart scanning, CAD User, Nov/Dec 2004).

During 2005 interest in the SmartLF 4080 soared as AEC, CAD and other users responded to its ground-breaking price and impressive entry-level specifications - a 40” image scan width, 400 dpi resolution, practical turn of speed, free scanning software and the necessary end result - sharp, clear images. The SmartLF 4080 series became a runaway success. Worldwide Colortrac’s unit sales leapt by 60%.

Despite the SmartLF 4080’s success it came in for some criticism. While its scan quality was high and ideal for AEC and CAD work the scanner was let down by an awkward paper feed and pressure mechanism made worse by the lack of a practical drawing Rewind option. Minor issues were quickly fixed by Colortrac but the Rewind problem proved more intractable. However, as the SmartLF needed to be re-engineered to meet new EU environmental regulations it gave Colortrac the chance to address this problem.  

The result is the vastly improved new Colortrac SmartLF Cx 40 model, launched in February 2006, which now replaces the 4080 series. The Cx 40 addresses the 4080’s main shortcoming - the lack of a Rewind button on the control panel - and adds 13 new features. Among these are 600 dpi optical resolution, advanced 2+4 wheel-drive Active Paper Transport and DNA (dynamic normalisation application), a transparent benefit lifted from Colortrac's high-end reprographics scanners to improve the Cx 40’s recognition of image detail.

The new SmartLF Cx 40 is faster, gives sharper images and is more user-friendly than the 4080 series. Its price and performance are so competitive that rival entry-level scanners, like the once leading Contex Hawk-Eye, now appear dangerously under-featured and over-priced.  

What’s new in the SmartLF Cx 40?  

At first glance the new Cx 40 looks much like an old 4080. Internally, the Cx 40 is driven by a new main electronics board, outwardly it sports a new man-machine interface with improved paper handling via a redesigned touch control panel. The SCAN and COPY buttons have been retained. The 4080's EMAIL button on the control panel has been scrapped. Scan-to-PDF is now a function of the supplied scanning software.

The scanner's control panel has a new LOAD/FORWARD button as well as a long-overdue and very welcome full-time document return option on a STOP/REWIND button - at last! Now SmartLF users can control drawing feed backwards and forwards through the Cx 40 just as in any expensive device. Thanks for listening, Colortrac!

One of the irritations on the 4080 series was the need to adjust the slider bars of the pressure mechanism for different thicknesses or qualities of paper, especially damaged or torn drawings. The slider bars were housed under an unwieldy lid design whose sharp catches were ever eager to nip your fingers. If you forgot to increase or decrease the pressure the drawings could snag or worse, tear. No more.  

In the Cx 40 the pressure mechanism and slider bars have been replaced by an entirely new Rolling Paper Hold Down. Double rollers automatically maintain an even pressure on top of the document as it passes across the sensor driven by the lower rollers. It gives the Cx 40 more flexibility to scan fragile documents while providing real pressure to flatten folds and reduce shadows in difficult to scan documents.

The Cx 40’s paper-feed mechanism limits scanned drawings to a paper thickness of 2 mm, the equivalent of 20 sheets of standard 80 gsm copying paper. It won’t, however, and unlike the Contex Hawk-Eye, take card or board. In our opinion, that's the ONLY benefit the Hawk-Eye can claim over the remarkable SmartLF Cx 40!

The Cx 40 uses an array of five overlapping 600 dpi Contact Image Sensors (CIS) to scan a 40” wide image. The 4080 had one long aperture glass, one of the SmartLF’s few consumable parts. If it became scratched the entire glass needed to be replaced. Now, in the Cx 40, each CIS sensor has its own hardened glass cover which can be individually, easily and more cost-effectively replaced by the user if any are scratched.  

CIS is a tried and tested technology used in low cost, desktop scanners. The scan data from the SmartLF's five CIS sensors is stitched together using Colortrac’s proprietary software. This worked transparently and without apparent data loss at the joins of the stitches in the 4080. The Cx 40’s improved document height control now adds an extra degree of stability to further enhance the stitch quality. But there are issues.

CCD scanner manufacturers (the traditionalists) are critical of the SmartLF's CIS technology for a variety of technical and commercial reasons. They argue that multiple CIS arrays cannot be stitched successfully; that accurate calibration of CIS arrays is impossible; and that CIS scanners are slower than CCD ones. None of these arguments remain true. They have all been largely resolved by technical advances in CIS technology.

The SmartLF's stitch quality is not always 100% perfect. Sometimes, when you zoom into the image it is possible to see breaks in the image at the joins of one or some of the stitches. The solution is to email a sample of your scanned image to Colortrac who will use this to reset the scanner's integrated stitching software. Colortrac will email you a patch back to update the scanner's firmware. Problem solved.

Whatever rival manufacturers say about CIS technology's need to stitch images together, Colortrac's solution works. The success of the SmartLF in the UK is proof that its stitching is a storm-in-a-teacup. Graphtec's sales success with their CIS range, particularly in the USA, proves the popularity and reliability of this technology.

More expensive scanners use Charge-Coupled Device (CCD) imaging technology, a combination of lenses, lights and mirrors which require sensitive, accurate calibration, secure housing and long warm-up times. CIS scanners make greater use of digital electronics, have no mirrors, etc, and use an integrated light source that needs no lengthy warm-up period. Switch on a SmartLF Cx 40 and off you go! It can be used within 35 seconds of power-on.

The downside of CIS technology is a poor depth of field. The Cx 40 cannot recognise fine colour detail as well as a CCD scanner. For most CAD applications the Cx 40's colour capability is more than adequate but it has its limitations. These can best be seen on drawings with highlighter pen detail. The relatively weaker light source of a Cx 40 scanner cannot pick up these metallic inks as well as a CCD scanner can.

The SmartLF 4080 was criticised for its insensitive feeding of crumpled and torn drawings from which it failed to extract results as sharp as those of CCD scanners. Colortrac addressed this problem by firstly giving the Cx 40 a new paper feed and hold mechanism that exerts even pressure across a wrinkled paper sheet, and secondly adding a brighter light source. The Cx 40 now gives better results from wrinkled drawings than the old 4080.

All of these improvement mean it is becoming increasingly difficult to tell good CCD scans from good CIS ones. You can no longer expect to buy any CCD scanner and get better results than you would from a CIS scanner. For example, the Cx 40 with a maximum 600 dpi optical resolution is capable of as good scan quality at 200 dpi as the CCD Contex Hawk Eye which is limited to 200 dpi optical, The fact is the Hawk-Eye simply cannot compete with the Cx 40. We expect the 200 dpi Hawk-Eye to be an early casualty of this new generation of scanners.

CAD users need practical scanning features which the SmartLF offers at a really attractive price. But it also offers clever stuff you can't benefit from. For example, while both the Cx 40’s 48-bit colour capture with 24-bit colour sampling and 600 dpi resolution sound impressive, there is little practical which CAD users can do with either. A 24-bit A0 image at 600 dpi will produce a file of 1.65Gb! This is marketing hype! 48-bit colour sampling is a check-box feature - it's something Contex scanners claim so now the Cx 40 can do it too!

Despite the uselessness of this feature, you can see where Colortrac are going with the SmartLF Cx 40 - head-to-head with Contex. This is good for CAD users as it means that wide format scanners will continue to develop in capability while becoming ever more affordable. The growing numbers of cost-conscious CAD users who can now justify the purchase of a large format scanner are doing so in large part as a result of Colortrac's aggressive marketing which has forced prices down. Thank you Colortrac!

In defence of wide format scanning at 600 dpi, I do concede that it is useful to anyone with a mega-powerful PC, (no doubt they too will grow more powerful), in particular GIS and mapping professionals and, most obviously, anyone who requires sharp, detailed scan-to-print image quality. Most large format printers, like HP and Canon, now recommend scans of a minimum 600 dpi for the best quality prints.

Colortrac's software is modestly priced by comparison to its rivals. ScanWorks (scan-to-file) adds the necessary professional scanning options while CopySmart (scan-to-print) gives control of colour print reproduction. In addition, Colortrac supply a free ISIS driver to connect to EDM systems and databases. Among the growing body of third-party CLASP (Colortrac Approved Software Program) products is Scan2CAD Pro raster to vector conversion software.

The SmartLF Cx 40 is a very impressive, new generation "entry-level" scanner. It's specifications and price/performance are formidable.

If your requirement is to scan AEC and CAD technical drawings in monochrome, grayscale or colour, a SmartLF Cx 40 has all the features you need, and more, to achieve sharp images for archiving or raster to vector conversion. Best, it does this at a price no other scanner can match at present.

There is considerable competition between UK resellers, so shop around.