A company that receives digital photos uploaded to its Web site, prints them, then sends the prints back by mail or courier.

The degree to which an object blocks light. Technically, opacity is expressed as a ratio of the incident light to the transmitted light.

Resolution also defines the extent to which a digital image capture system, such as a scanner or a component thereof, can display image details.

The manufacturers of scanners usually specify the resolution of the built-in sensor as the optical resolution. This specification refers only to this one component. However, due to the complex structure of a scanner (including optics, mirrors, electrical components such as A/D converters and cables (shielding)), the actual usable resolution may be lower.

But since the actual usable or effective resolution is the one we are interested in, we define optical resolutions as resolutions that the scanner with all its components actually achieves. This resolution can be measured with our USAF 1951 Resolution Targets.

An optical zoom is made to bring you closer to your subject, without you having to move. Zooms are constructed to allow a continuously variable focal length, without disturbing focus. To achieve this, the optical zoom uses a combination of lenses that magnify the image prior to being registered at high resolution by the sensor. While the digital zoom only changes the presentation of existing data, the optical zoom actually augments the data collected by the sensor. Optical zooms are superior to digital zooms.

Black-and-white emulsions that are not equally sensitive to all colours of light. They are more sensitive to blue and green, but not sensitive to red light.

The detail and clarity (achieved by tightness of dots) with which the image will be displayed or printed (dependent on the capability of the display or printing device).

Exposing the image sensor to more light than is needed to render the scene as the eye sees it. Results in a too light photograph.

Printing over areas already printed, as opposed to using a knockout.

Scanning at more than an optimum sampling rate.