User's Manual Part 1

When computers get involved in the color process such things as memory capacity and data
compression become factors. Fifteen-bit color yields 32x10
3
shades and a requires 15-bits for
each pixel in the desired image. Twenty-four bit color yields 16x10
6
shades. Thirty-two bit color
yields 4x10
9
shades. Note that the memory required for images expands substantially with the
number of shades. Compression attempts to reduce the memory requirements. Some
compression schemes only attempt to identify repeating colors. Others, such as JPEG, can treat
various amounts of change as if they were the same repeating colors. Carried to an extreme, a
posterized result would occur, and the color changes would step unnaturally.
In the color printing process, particular shades of color derive by mixing quantities of the basic
colors cyan, magenta, yellow, and sometimes black (usually referred to as CMY or
CMYK—where K designates black). When users choose some other color definition from their
application—e.g., hue saturation intensity (HSI) or red green blue (RGB)—a conversion to
CMY/CMYK must take place to support a printer. Mixing occurs at the level of each pixel. Pixels
serve as the basic elements of images. Pixels can comprise either one dot (the smallest printable
element) or a small matrix of dots, depending on the methodology used to form the images.
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 deliver RGB
outputs.
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 (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). The color perceived results from the optical mixing of the eight
possible color components contained in the matrix.
With eight dot colors possible, a four-by-four dot matrix can produce in excess of 4 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 3M MAXSecure printer, this same
matrix can produce 16 different gray shades 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 monitors occurs from control of beam
intensity, with three beams acting on the individual phosphors applied to CRTs (cathode ray
tubes).
Of all these methods, Dye Sublimation produces the best quality printouts, because as is the case
for all 3M MAXSecure printers, each dot can have the full range of 15-bit color (32K shades) at
full 300 dpi resolution. In fact, even with resolutions equal, Dye Sublimation still has an
advantage over offset printing. Dye Sublimation creates a dot color by varying the density of the
CMY dyes. Offset printing creates a dot color by varying the diameter of the CMYK ink dots,
3-2
980286-001 Rev. A
CHAPTER 3
THEORY OF OPERATION