Is more than 16 million colors enough? You'd think so wouldn't you? There are cases however when more would be better. Consider for instance, photographing a rose with vivid red colors. Your 24 bit palette has in effect, just 255 levels of pure red to portray the flowers color subtlety and this number isn't nearly enough. That's why a capture system that's 30 bit or 36 bit is better. More color and tone choices. Even if the end system such as your computer screen is only 24 bit, more bits in the beginning means that you can choose the BEST 24 bits.

A problem peculiar to scanners and line scanning cameras, where a line of sensors moves steadily across a gate, is that of stepping. Causes vary from harmonics with pulsing in the light source, electrical signal noise, to more obscure reasons. It's most common and noticeable in the shadow regions where sensors are pushed to the limit but can appear in any part of the image. Here's a little hint when evaluating these devices: Create a scan, then in a program such as Photoshop view at 100%, go to curves or levels, radically lighten the image, and look for stepping artifacts. These will appear as lines of different density and / or color.

Mike Berceanu has been doing commercial and advertising photography for over 20 years, specializing for the last seven in digital imaging. Born in Brisbane, Australia, he now lives and works in Sydney where he also teaches and writes. His specialties include photo manipulation and composites from multiple images, which he photographs and combines to his clients' specifications. He is at ease with all film formats from 35mm to 8x10 and does his digital imaging on a MAC using Adobe Photoshop, Live Picture and MetaCreations Painter.

Web Site: http://www.berceanu.com.au
Email:       mike@berceanu.com.au