Grayscale - This is the use of many shades of gray to represent an image. Gray scaling is the process of converting a continuous-tone image into an image a computer can manipulate. Dithering simulates shades of gray by altering the density and pattern of black and white dots. In gray scaling, each individual dot can have a different shade of gray. Color - Color scanners use a series of filters, usually red, green and blue, to measure the different color values in an image.
Most scanners use one pass of the light over the image to record the data for each filter.
This is why color images can be so much larger than monochrome images. In other words, for a monochrome image the machine is only storing one bit of data per pixel. It has to store 24 bits per pixel for a true-color image. Each Acer must pass rigorous testing and inspection before being shipped. Technology that makes scanning easy, helps you make every scan perfect, and saves you time.