CHAPTER 3
Offset printing and Dye Sublimation can produce a substantial range of colors within just one dot. Color Monitors produce their range of colors using a red, green, and blue (RGB) three-dot matrix. Scanners and digital cameras employ charge-coupled devices (CCDs) that capture and deliver RGB components.
Thermal Transfer and most Ink Jet printers produce their range of colors using larger dot matrixes—typically up to four-by-four or equivalent dots—where each dot color can be a fundamental (CMY) or the combination of fundamentals (which adds RGB and black). Therefore, these particular devices limit their dot colors to cyan, magenta, yellow, red, green, blue, black, and the media color (usually white). Since these colors remain unmixed, color perception beyond the eight relies on a person's natural tendency to mix dot color components where associated dots appear too small for individual perception.
With eight dot colors possible, a four-by-four dot pixel matrix can produce in excess of four billion combinations ((4 x 4)8). However, as long as the color components remain the same, the dots in a matrix can be shuffled into any pattern without changing the color perceived. For example, a matrix containing all-white dots except for one red dot produces the same shade of pink no matter where in the matrix the red dot lies. Therefore, a matrix containing n dots can produce each color in n different ways. This makes a four-by-four matrix capable of producing more than 268 million different shades ((4 x 4)8/16 + white). For monochrome printing, which is the only matrix-based printing that users might want to apply to a P-Series printer, this same matrix can produce 16 different gray (or other thermal transfer ribbon shades) levels plus white ((4 x 4)2/16 + white).
Mixing of dot colors in Offset Printing and Dye Sublimation occurs by controlling the amount of each dye or ink that gets applied to each dot. Mixing in color monitors occurs from control of RGB intensities. For CRTs (cathode ray tubes) three beams act on the respective phosphors. For Active Matrix Displays, liquid crystals emit the RGB levels.
Of all the methods, Dye Sublimation produces the best quality printouts, because as is the case for all P-Series Printers, each dot can have the full range of 15-bit color (32 shades per dye color) at a full 300 dpi resolution. In fact, even with resolutions equal, Dye Sublimation still holds an advantage over offset printing. Dye Sublimation creates a dot color by applying varying densities of the CMY dyes. Offset printing creates a dot color by varying the diameter of the CMYK ink dots, which can make individual dots more observable and subject to moire pattern generation. Since without magnification no one can see individual dots at 300 dpi and since each dot results from percentages of YMC ribbon colors, Dye Sublimation offers card printer users essentially the continuous-tone quality of photographs.
Moire (typically herringbone) patterns can become a factor when users generate either print files or hard copy separations for offset printing. Users creating related print files typically ask the people that do their offset printing which separation angles best reduce these patterns before risking a distorted result. Many applications offer Print Dialog options for these settings.
All the non Dye Sublimation print methods work because we naturally mix dot colors that appear too small for individual perception. To see individual dot intensities or colors, view the monitor or printed page using an Eye Loup or other such magnifier.