More bits aren't always better
- 16 July, 1997 14:20
Like their personal computer counterparts, desktop scanner manufacturers generally revamp their products to provide more power for less money over time. Following this trend, some of the new, low-priced scanners offer amazing specs. But are more bits better? Not necessarily.
True, these scanners capture more data than their 24-bit siblings. Where most scanners record 8 bits of colour per channel - red, green, and blue - high-fidelity scans contain 10 or 12 bits of data per channel; the final image is downsampled to 24 bits before it's sent to the computer. High-fidelity technology has existed in higher-priced scanners for years, but hasn't been available below around $2000 until recently.
In theory, this process lets 30- and 36-bit scanners create a superior copy of artwork, but because much of the image quality rests on the integrity of the hardware and the inter- polation process, higher bit depths don't necessarily translate into better results.
US Macworld Lab tests evaluate the objective measures of scanning success: speed and image quality. But as good as a scanner is, its bundled software should be a big factor in choosing a model. Although acquisition software isn't - and shouldn't be - a replacement for high-powered editing applications, you should be able to perform basic tasks like tonal corrections, scaling, and image sharpening before making the final scan.
Not wanting to miss the latest trend towards document- centric computing, this class of scanners is hyped as a complete document-organisation solution - they're not just for digitising artwork any more.
Their bundled software converts documents to editable text via (OCR), and they can fax or print your scanned documents in a single step, in effect making your scanner into a desktop fax or photocopier. None of these capabilities are particularly innovative, but they've become more convenient year by year.
But don't assume that you can put a newsletter on the plate and magically end up with a full-blown Web page full of formatted text and graphics. Using this method, photos and graphics aren't placed (or even scanned), and text translation isn't a one-step process. Frankly, anyone with even rudimen-tary DTP skills could do better in less time.