Canon CanoScan FS2700F User Guide - Page 20

Setting the Scan Mode STEP 2 When an image is scanned, it is read as a collection of "dots." The scan mode that is selected determines how each of these dots is represented in the output. The following five scan modes are available. Black & White Mode The Black & White mode can reproduce a dot as either black or white. Half-tone colors, such as gray, are automatically reproduced as either black or white also. Consequently, the Black & White mode is more suited to textual documents or line drawings than complex images with color gradations. 8bit Grayscale Mode In the 8bit Grayscale mode, each dot is formed by assigning it eight individual "bits" of data. By combining these bits in various different ways, a dot can be expressed in 256 distinct shades. Photographic images are reproduced relatively naturally in this mode, but the file size is much larger than that produced by the Black & White mode. 12bit Grayscale Mode (FS2710 only) In the 12bit grayscale mode, each dot is formed by assigning it 12 bits. In this mode one dot can be expressed in 4,096 individual shades. The size of an image saved in this mode is approximately twice the size of an 8bit grayscale mode image. However, the displayed image is the same as the 8bit grayscale mode image because the difference in the image quality cannot be accurately reproduced on the screen. Use this mode when you need an monochrome image with finely attenuated shades of gray. 20 20