The reason most people are a bit vague about scanners is that they don't use them all that often, at least not like printers. And, although they understand that scanners probably work along the same lines as the familiar photocopier, few people are sure exactly how they work. With printers, for example, the squirting of ink onto paper is an idea you can grasp; transforming a physical image into a usable file in our computer is not. Introduce to scanning the concept of optical character reading software which transmutes ropy old magazine pages into more or less pristine Word files and the mists of incomprehension descend further.
Furthermore, because scanning is not something people do all that regularly in architects' offices, and because using the software often involves quite a lot of reading of the manual, poor-quality scans are common. Scanner and software manufacturers are doing their best to simplify everything.
But because of all the uncertainty, the average scan is likely to be inappropriate for its use - usually at far too high a resolution and thus with a far larger file size than it need be on the office hard drives. PowerPoint presentations and Web site images can be quite low resolution - less than 100dpi. But even though this magazine is printed at only around 300dpi, photographs will, depending on their size, be scanned at the printers at a higher resolution. It's worth reading the manual and telling the staff what they can probably get away with. Scanning at maximum resolution just in case is really wasteful of time and hard disks.
So are scanners any use and what do architects use scanners for? We're talking here about flatbed scanners, not the rotating devices used in upmarket print shops.
The answer to the first is an unequivocal yes and to the second - it depends. A straw poll among half a dozen offices suggests that scanners are used widely for such things as getting images into PowerPoint for directors' on-screen presentations. They are used for transforming hand-drawn sketches into computer images which can then be played around with using, say, Photoshop or an image-manipulating application. They are used for jobs involving existing buildings or for conservation work where the orthogonal nature of the average CAD program means that it is easier to do things by hand.
And that kind of thing. The practices we have spoken to believe that using an inexpensive scanner for everyday images is fine in combination with the less frequent use of a print shop for really high-quality work.
For practices which have not gone entirely over to computer-generated drafting, or which are managing the transition from one to the other, big scanners are more or less essential. They are used to make electronic copies of hand-drawn production drawings and, although this is apparently not supposed to happen, to enable hand-drawn amendments to electronic drawings which it would be too tedious to unearth from the computer and print out.
This kind of scanner has to be around A0 in size and is very expensive - ten grand and up. Oce's Colour System 4040/4050 series scanners can cope with widths of 127cm (and on boards up to 15mm thick) at a scanning speed of 3.3cm/second. Other manufacturers of wide-format scanners include Linotype-Hell.
Practices which have made the change to CAD tend to have only A4 scanners, although most would prefer to have an A3 scanner on hand. They don't because although doubling the size of the scanned image doesn't remotely double the complexity of the mechanism or its manufacturing processes (the parts are just a bit bigger) the price for A3 kit is significantly higher. Thus A3 scanners cost from £800 (say the Epson GT 1000) up to three times that (the Epson GT12000 with OCR software) - although there is the A3 Mustek ScanExpress at a seemingly impossible £116.
That latter price is around the middle for low-end A4 scanners: Hewlett-Packard's two cheapest are either side of £70. Its standard non-sheet-feeding office machine is the ScanJet 5300C at around £165. Other names offering A4 scanners in the £100 to £500 range are Agfa, Canon, Nikon, Epson, Microtek, Umax, Black Widow and Linotype. Although it used to be rule of thumb economics that office scanners should cost in the low thousands and that the sub-£100 machines were toys, the price of scanners has, with changing scanning technology and volume production, fallen dramatically since then. In a recent magazine test, the best scanner in the test was the Epson Perfection 1200Photo at around £200. The AcerScan Prisa 620UT at around £130 came second and showed well in other magazines' tests of inexpensive scanners.
It used to be conventional wisdom that a SCSI interface was best. Now most PC scanners come with a USB interface which apparently performs as well as its older rival. Manufacturers make a great deal of their resolution figures which are normally expressed in pixels per inch (ppi). You shouldn't take too much notice of them - the manufacturers' claims, that is, because they refer to an ideal rather than actual performance. The only practical way to discover the quality of a scanner's resolution is to keep an eye out for comparative tests in magazines you think you can trust.
That's also true for colour accuracy and speed. Don't forget, an untrained person can take hours of trials to produce an adequate scan, so manufacturers' speed figures may turn out to be irrelevant.