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Drum Scanners

Generally drum scanners are of an impressive size, and correspondingly expensive, costing around as much as a car or a small house. These are used by pro labs to scan your film, so it is hardly surprising that a high resolution scan can cost $50 to $100 a time. The drums used are typically a metre or so long, and a number of images are scanned at the same time, each negative being held on a small part of the drum's surface.

The light source is in the middle of the drum, and the photocell outside. As the drum rotates, it scans every point on a circle around it. The light and photocell then move a fraction parallel to the axis of the drum for the next line to be scanned. The curved drum keeps the film to light source distance constant, and avoids problems with reflections.

Oil Mounting

Dust and most of the surface defects such as scratches on film become invisible if the slide or negative is immersed in suitable oil with a similar refractive index to the film. This is a technique much used on drum scanners and high-end flatbeds.

Removing the oil after scanning can present some problems, but is generally faster than the time otherwise spend in retouching to remove the dust. The oil also ensures good contact with the drum.

The best drum scanners can give scans as good as the best high-end flatbeds, and generally better than those from most film scanners. However, if you use 35mm film and the one of the better film scanners, the differences may be hard to discern.

Virtual Drum Scanners

Imacon scanners use what they call a virtual drum. In these scanners, the film is curved by applying a slight pinch across it. This creates perfect flatness along the film at right angles to the curve, and Imacon claim it gives the advantages of a drum without the size and cost implications.

The cheaper scanners in the Imacon range are popular with some pro photographers, claiming to give drum scanner quality at a much-reduced price. It is always difficult to assess such relative claims, especially without being able to work extensively with a wide range of expensive professional level scanners.

However, there is no doubt that the Imacon range is competitively priced and can produce good results. They are also much smaller than a drum scanner, which may be an important factor.

Which scanner should you buy?

Your choice of scanner type may be largely dictated by your budget. If you are an amateur photographer, you may find a flatbed with a transparency adaptor does all you need, or you may consider having both a flatbed and one of the cheaper film scanners.

Professionals are likely to find that their needs are met by one of the better film scanners, especially one of the medium format models from Nikon or Minolta. Scans from these are generally perfectly acceptable for reproduction purposes, so long as you learn to use them effectively. If you don't tell people they are not drum scans, they will probably never know. You will probably also want to get one of the better consumer flatbeds for scanning occasional prints, possibly with a transparency adaptor for rough scans of 4x5" films.

If you are using large format, then for professional use you will want a drum scanner or high-end flatbed (or possibly a virtual drum.) Unless you are part of a larger studio setup you will probably find it preferable to have you scans made for you. If you intend to buy a scanner, you need to study the available information on these carefully and to get examples of your work scanned on the machines you are considering buying. The prices for the best drum scanners such as those from Heidelberg get pretty elevated.

As for which make you should buy, this is harder, as it depends on your exact requirements. I've bought and used scanners from HP, UMax, Microtek, Epson, Canon and Minolta and have generally been happy with all of them. If I was replacing my current flatbed I would probably buy another Epson, but that doesn't mean they are any better than those from other manufacturers.

Were I to suddenly come into large amounts of money, and be able to set up and maintain an expensive studio full of equipment, the scanner I'd be interested in would be the Creo-Scitex Eversmart Supreme, an A3+ flatbed which scans at 5,600 ppi and has a density range of 0.3 to 4.3, but costs rather more than my annual income.