fewer, effectively larger pixels. This process always samples the entire image area, does not skip lines, and thus is immune to aliasing caused by subsampling (skipping pixels).
These lower resolution selections average more CCD data values together to produce the larger pixels; this averaging lowers the CCD noise levels, and increases the bit depth of the image beyond the specifications of the
For resolutions greater than 100% (SuperModels only), the scanned width of each line is decreased by reducing the distance the sensor moves in the insert, thus adding additional real pixels between the positions normally scanned. In the direction of the sensor (short dimension), interpola- tion is used to redistribute the captured information over additional pixels. Since the scan direction (long dimension) is always giving real pixels, the result is more accurate than techniques that interpo- late in both directions and results in sharper images. In the worst case, 3 pixels are made from 2 real pixels.
If an exact image output size cannot be obtained at one of the available resolution selec- tions, it is usually better to select a resolution that produces a file larger than needed, and subsequently reduce it to size in an image editor like Photoshop.
In many cases, but not all, cropping can be used in conjunction with the resolution selections to produce the exact file size required. This method may involve changing the camera position or magni- fication (image size) to fit the image into the desired crop box. The choice of predetermining the exact camera positioning and the specific file size, or
For a given scan area, lower resolution settings also produce shorter scan times due to the require- ment for fewer lines in the scan. This relationship is linear; for example, reducing the number of lines by half will halve the scan time.
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