Product Reviews

This review is part of a comparative test between Agfa DuoScan HiD, Microtek ArtixScan 1100 and Umax PowerLook 2100XL.

These days flatbed scanners are very much a commodity items commonly found in home setups as much as on business desktops. Less than £100 will buy you a decent scanner, but if you're prepared to pay a little more you can add on transparency adaptors and automatic document feeders for extra versatility. But this ignores the realm of professional, creative scanners which start at around £1,000. We take a closer look at three of these high-end flatbed scanners to find out exactly what they can do that a humble £100 device can't.

One thing the three products have in common is that their manufacturers - Agfa, Microtek and Umax - not only enjoy a good name in the professional graphics and pre-press industry, but they also sell low-end devices to home and business buyers. You have to wonder how a manufacturer can happily build high-end, precision machines while churning out lightweight translucent consumer scanners.

The situation is even more complicated than that. The three scanners reviewed here aren't exactly high-end scanners either. All three companies build true pre-press devices costing in excess of £4,000, so think of the £1,000 to £2,000 range as catering for marketing departments, production desks and graphic designers.

Another feature the three have in common is a SCSI interface. Although high-speed parallel ports and even USB connections are fast enough for everyday personal scanning tasks, the high resolutions handled by professional scanners demand a faster throughput.

Resolution and colour depth

The Agfa DuoScan HiD and Microtek ArtixScan 1100 are machines based upon the same basic scanning mechanism, both supporting a sampling rate of 1,000 x 2,000ppi (pixels per inch). The Umax PowerLook 2100XL supports 800 x 1,600ppi. The first figure in the pair refers to the number of pixels that can be captured per inch of the scanned original by the CCD array along the scanning arm. After this comes the increment at which the scanning arm moves along the glass plate. The optical sampling limit, therefore, is 1,000ppi for the Agfa and Microtek products and 800ppi for the Umax.

This is an important distinction, as scanning any higher than the optical limit adds absolutely no more image detail whatsoever. Instead, the scanning software just interpolates extra pixels based on adjacent colours to fill out your desired resolution. But even so, you can find plenty of consumer scanners that support 600 x 1,200ppi optical sampling, which isn't far off Umax's 800ppi - so you may be wondering what you're paying for (see Is it really worth it?).

Also note that despite its lower sampling rate, the Umax PowerLook 2100XL costs a good deal more than the other two products at £2,199. The difference in price is actually due to physical plate size, since the Umax scanner is an A3 device as opposed to the Agfa and Microtek which offer just an A4 scanning area. The kind of person who buys an A3 scanner is almost certainly looking to scan large originals which will be reduced for printing. Hence, there's no great need for ultra-high resolution captures. The 1,000ppi of the Agfa DuoScan HiD and Microtek ArtixScan 1100 makes them better optimised for scanning small originals for enlargement, especially transparencies.

Colour depth is important for professional scanning, although many manufacturers use it as just another 'big number' to print in their advertising. In effect, 24-bit colour is made up from devoting eight bits per colour (red, green and blue) per pixel. These eight bits essentially allow 256 levels of each RGB channel, the 24-bit combination ultimately representing a top potential of 256 x 256 x 256, which equals 16.7 million different colours. By increasing the number of hardware bits devoted to each pixel, a scanner should, in theory, be able to deal with a bigger overall colour space rather than 'clipping' everything it sees to fit within 256 levels.

All three scanners support a 42-bit colour depth, meaning 14-bits per colour channel, per pixel. In practice, you can use this additional depth to maximise the breadth of tonal ranges captured in a standard 24-bit destination scan, or use software controls to make a raw 42-bit capture which can then be sent to Adobe Photoshop in 16-bit per colour mode.

Associated with colour depth is 'dynamic range' or 'optical density'. Generally speaking, this refers to the ability of a scanner's CCDs

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to perceive tiny tonal variances in dark areas. The Agfa and Microtek scanners are rated at an impressive 3.7D, while the Umax product is rated 3.4D. However, at the end of the day dynamic range is determined by the makeup of the original scanning image. A photographic print, for example, can't produce enough spectral reflectivity to reach past 2D no matter how sensitive the scanner is. Dynamic range, therefore, is only really relevant when scanning transparencies, which backs up my view that the Agfa and Microtek devices are better geared towards this kind of task.

Methods of capture

Despite its distinctive blue casing, the Umax PowerLook 2100XL is relatively conventional in make-up. All originals, whether reflectives or transparencies, are placed face-down on the large glass plate and the lid closed during scanning. The lid contains a second lamp which shines from above the plate when scanning transparencies. It's unusual only in employing a new moving mirror structure which extends the path of the scanning system and allows the use of lenses with a longer focus, thereby improving image quality. Umax is likely to introduce this system in new releases of its professional product range.

The Agfa DuoScan HiD and Microtek ArtixScan 1100 employ a different structure known as twin-plate. This eschews the conventional transparency adaptor lid-with-lamp in favour of a transparency scanning plate actually inside the main body of the unit. You still place reflective originals on the top glass plate and lower a lid to keep them in place, but transparencies are treated differently. These are mounted in special holders, or arranged loosely on a plain glass plate, which can then be inserted into a horizontal slot at the front of the box. Since the plates are entirely separate, you can open the lid and rearrange your reflective artwork while transparency scanning is taking place, and vice versa.

Mounting slides, negatives and general transparencies into special guides sounds taxing, but once you see the results it all begins to make sense. If nothing else, twin-plate systems effectively remove the glass sheet from flatbed transparency scanning, so minimising problems caused by trapped dust and Newton rings.

In other words, the Agfa and Microtek scanners achieve a purer capture with the minimum of objects between original and lens. The Umax scanner makes very good transparency scans too, but not quite as impressive as the other two.

Simply put, the sheer size of the Umax's A3 scanning plate means you can lay down more than a couple of dozen slides in one go and set up a batch routine to scan each one individually but automatically.

The bundled benefits

Batch capture is a key feature of scanning software at this level, and is supported by Agfa's FotoLook, Microtek's ScanWizard Pro and Umax's MagicScan. These utilities offer extensive control over scans, including colour correction based on pre-scans, but they're not themselves intended as advanced image-enhancement applications. For this reason, Microtek bundles a copy of Lasersoft SilverFast which offers superior pre-scanning and correction tools, including selective unsharp masking previews.

With the PowerLook 2100XL, Umax bundles a copy of binuscan PhotoPerfect RGB & CMYK which isn't a scanning application at all, but an image post-processing engine that operates automatically in conjunction with MagicScan. SilverFast is ideal if you want nitty-gritty control over every aspect of image scans, while PhotoPerfect is astonishingly adept at making colour enhancement completely automatic.

Colour accuracy and consistency relies in no small part upon good calibration. All three scanners come with software calibration utilities and photographic 'IT8' target images (as shown on p200). You need to scan the target and let the utility compare coloured areas in your capture with what they ought to be according to the manufacturer. The result is an ICC colour management profile which will help to maintain accuracy in future. Of the three devices on review, Agfa puts the biggest emphasis on calibration by including its professional colour management utility ColorTune.

A final word ought to be said on the subject of warranties. Having spent this much money, you'd expect on-site service or a swap-out if anything should go wrong with any of these scanners. Accordingly, Microtek promises two-years on-site cover and Agfa offers three. Umax is a little lacking in only giving a one-year return-to-base warranty - a bit tight considering the bulky size of the PowerLook 2100XL, not to mention its £2,199 price tag.

Otherwise, it's clear that the Agfa DuoScan HiD and Microtek ArtixScan 1100 work well as photo, line-art and transparency scanners. In fact, fine-quality originals will generate scans that are good enough for high-end pre-press. The Umax PowerLook 2100XL, on the other hand, is more of an all-rounder for the creative designer in a studio or a marketing department, offering a large scanning area and capturing professional-quality images for incorporating into other digital artwork.