Digital Photographs vs. Scanned Images

Digital photographs share traits with scanned images but also have some unique attributes of their own. Here are some of the ways in which they differ :

Size Consumer- and prosumer -quality digital cameras usually produce smaller images than scanners do. Their image size is limited to the capacity of their CMOS or CCD sensor chip. Their resolutions and file sizes depend on the amount of data their detectors can collect and process. Advertising materials often describe the resolution of a digital camera measured in megapixels. For example, a 2.5-megapixel camera will have a sensor that converts the image into approximately 7,500,000 pixels (2.5 million — 3 channels ”red, green and blue).

Functionality Digital cameras work best when used in the same way you d use a traditional camera. Many do not capture pages or printed photographs particularly well, although they can be used in a pinch to create relatively low-resolution copies of printed material.

Blue Channel In many CCD-based digital cameras, the blue channel displays more noise than the red or green channels. This can be quite pronounced in some digital photographs. To correct this problem, the blue channel can be blurred slightly with the Gaussian Blur or Despeckle filter in Photoshop. As camera sensors improve, this noise is being reduced.

Noise Noise in digital photographs tends to be the product of low lighting conditions. As I said earlier, one of the best ways to avoid noise in digital snapshots is to increase ambient light. Of course, an even better method is to purchase better-quality equipment with better sensors ”and also use more light.