Consumer scanners have progressed dramatically in their capabilities and image quality over the last decade. Now, affordable scanners may be purchased as stand-alone machines or as part of multi-function document solution. Choosing the right scanner does require a general understanding of the varying capabilities that are prevalent in today's machines, which begins with a broad introduction to what is out there.
All consumer image scanners can be divided into a few categories. Flatbed, sheet-feed and duplex scanners are the most common choices that meet the needs of most consumers. Specialty image scanners such as drum and wide format scanners are specifically targeted toward industry professionals that require immensely high resolution scanning and other necessities of the professional market. For most consumers, the three listed scanner types from above will meet all of one’s productivity requirements.
Many consumers are choosing to purchase a multi-function machine that has an incorporated flatbed and sheet-feed scanner, like the Canon MX700 ink. These scanners represent significant improvements over the included scanners of a few years ago, but the specific qualities can vary. A dominant variable in these types of scanners is the color depth capabilities. Color depth refers to a measurement of the number of tonal differences a scanner can produce in a digital image. Common color depth measurements include 8, 16 and 24 bit depth. There are machines that are advertised at 48 bit color depth, but these are rare and not widely practical due to incompatibility with many current image programs. The basics of color depth are that higher bit depth offers greater subtle tonal representation within hues. This allows for greater fine tuning of color to more accurately represent images as the human eye may have perceived them originally.
Interpolation is another frequently touted specification by manufacturers because of the high resolution numbers it is usually represented with. However, the true functionality of a scanner is most accurately represented by its optical resolution. Interpolation is a digital way of increasing the size of a scanned image beyond the capabilities of its optical parts. A simplified explanation of how interpolation works is that the machine will actually replicate the pixels of an image to create larger images. This function produces varied results because some firmware is better than others, but ultimately it is only a useful function if one's output needs to be significantly larger than the original image being scanned.
One of the greatest distinguishing specifications among scanners is speed. High speed scanners use various techniques to accomplish faster scan times. The difficulty can be in determining what a scanners speed is at a desired resolution as many scanners will list their faster speeds that are typically associated with lower resolution images. Sheet-feed scanners are faster overall than flatbed scanners because they greatly reduce the time needed to change the page. Duplex sheet-feed scanners reduce speed even further by incorporating two single-pass optics capable of scanning both sides of a page simultaneously.
Ultimately, choosing the right scanner will depend on your resolution, color depth and speed needs.