Flatbed scanners... points of discontent

Drop-dead-gorgeous photo reproduction.
The best flatbed scanners are in fact your office photocopiers. They are easy to use and provide you with proper copies and scans of your documents and pictures. They are a necessity for a modern office. On the other hand, flatbed film scanners are glorified photocopiers. If you are looking for a snapshot, they all do the trick. If you are looking for high-end drop-dead-gorgeous photo reproduction, then they fall short of meeting the color nuances and picture resolution requirements to get you a magazine cover. Here is why.

There is nothing flat about a flatbed scanner.
The major players in the photocopier industry, such as Minolta, Xerox, Canon, do not produce high-end flatbed film scanners. They know that this technology has its engineering limits. Most technical support would agree that when the lamp burns out it's time to buy a new scanner. First, there is nothing flat about a flatbed scanner. What I mean is that photographic film is curved and requires perfect flattening before being scanned. The reason is that the image exists in a micron-thin layer, the film emulsion. Therefore, to make a complete image capture, you have to be in perfect focus all the way to that micron layer at the photographic grain level, across the whole film surface, and for that the emulsion has to be kept totally flat. It appears that a flatbed cannot achieve this with any level of consistency, despite the sometimes high price point. This is basically because it relies on stitching together a sequence of digital shots as it moves.

Sleepy color on flatbed.
At a good scanning speed (the speed of photocopiers) you get optimum results, a very decent snapshot of the original, postcard size. But to get higher resolution, you need the speed to slow down almost to a halt. This is where all the problems show up. Humidity, heat, rail friction, motor vibrations, wear from use, gear backlash, lack of flatness of the original transparency, etc., all contribute to throwing the scan off a steady resolutions path. As a result, it cannot stay in constant focus to the micro-photographic grain. The higher the resolution, the more cumulative effects show up. In the worst of scenarios, you get random streaking effects. To perk up a sleepy scan, you have to resort to sharpening software gimmicks and interpolated file sizes, followed by some PhotoShop afterglow. All of this has little to do with high-end color information capture. (If your aim is, for example, to build a true photo archive digitally, you really should capture the information in its full color nuances and in sharp focus in the first place. It has been the curse of several international museums, which jumped onto the flatbed rails, to awaken, thousands of scans later, to a collection of pixelated pictures, in wrong formats, wrong color space, and wrong file resolution.)

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The "feed-me" flatbed scanner.
The worst of flatbeds are probably the type where you feed one slide or one film at a time. In addition to a severe loss in production workflow, so-called high-end, high-priced flatbed scanners ($15k+ US) have all the problems you find in photocopiers (Remember that yearly maintenance package deal, 5 cents a copy, plus toner?), including lenses that create rainbow flares in highlights, particularly noticeable toward the outside of originals. The edge flaring effects are often worse on originals that are mounted away from the optical center of the scanner.

Is a flatbed scanner a digital camera on rails?
Like digital cameras, flatbeds use the exact same CCD capture chips. CCDs sense heat not color. The transfer interface software to produce a decent pictures is in its infancy. CCDs have still a long way to go in their technological quest to match the color nuances and resolution of film emulsion. The bottom line is that there is nothing "easy to use" in high-priced flatbed scanners when you have to fix "digital blur" afterwards, for hours on end. That said, I love my low-end flatbed scanner/photocopier/fax, at $200, it's a snap. You get the picture!

What's wrong with CCD chips?
Digital cameras, even at the pro level ($10k US and up), are known to have good image capture in midtone and lower highlight areas. But CCD chips are also known to have shortcomings in extreme light situations. Sometimes, the bright highlights have flare or are bleached out, or the deep shadows, on the other end of the scale, are blocked solid. This is particularly the case when the exposure is made in bright sunlight. Although a good range can be captured, the tone separation toward both ends is often lacking. Color breaks or pixel bandings show up unpredictably.

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Flatbed limited range of  brightness.
This would normally not be a problem in a flatbed scanner where the light environment is well under control. But, as we know, most of the originals/transparencies you get for scanning are usually slightly or severely underexposed. Therefore, they fall into the very area where CCD chips have the most problems in resolving tonal separation, namely, the deep shadows and the 3/4 tone areas. Forcing successful contrast gain and tone separation at one end of the scale often does not occur without compromising somewhat the other end of the scale. This brings us to a point quite often misunderstood: many flatbed manufacturers claim that their devices are capable of a density range of 4.0 to 4.5, a range comparable to the one found in drum scanners with PMT (photomultiplier technology). If you were to make densitometric measurements, you would find that, from extreme whites to extreme blacks, the claim might be true. What is not true is that the subtle shifts in tones and densities between the extremes, a range for example from 3.0 to 4.0, can be separated into clear and constant density steps. These misleading claims are as blurry as the tones and color nuances that flatbed scanners fail to separate, simply because of the technological limitations of CCD capture chips.

The better flatbed scanners on the market.
If your are absolutely set on acquiring a so-called "high end" flatbed scanner, here is the list according to many expert reviews of the better ones in order of preference: The Scanmate F14 from ESCO Graphic, the Scitex Eversmart Supreme (now made by CREO), and last, the Fuji Lanovia. All of them are very pricey, $20K to $50K. That said, I would certainly not recommend the purchase of a secondhand model.

Nelson Vigneault, CEO, CleanPix Corp.

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