Graphics Programs Reference
In-Depth Information
Fig. 6-11
A 2D gamut
map shows the differences
in the color gamut of the
two profiles for the Epson
2200 made using the Vivid
driver setting (yellow)
versus the No Color
Adjustment setting (white).
Notice that the Vivid
setting produces a slightly
larger color gamut in the
saturated blues, whereas
the No Color Adjustment
shows more gamut in
greens and reds.
Setting different paper options in the driver also plays a role in ink delivery and resulting
profile quality. Most users profile their printers using a mode whereby they get the maximum
gamut and hope that either prelinearization or sufficient target patch samples will account for
this poor behavior. Alternately, you can attempt to substitute a different printer driver by using
a third-party print driver or RIP. These issues are not solely limited to ink-jet printers. My Pic-
trography 4500 has four settings in the export module that affect how data is sent to the printer.
To pick the best settings, you can build a profile for each and examine the color gamut using
a utility like
ColorThink
(see Chapter 8) or testing the final output. However this process is both
time consuming and expensive.
You can print out a sample image containing RGB and CMYK step wedges running from
zero to 255 in 10 or 15 percent increments. Such a file, named
InkDensity.tif
, is supplied on this
topic's CD. Output this file using various settings and visually examine the patches to see which
provides the best tonal separation. Keep in mind that the driver setting that provides the best
separation may not be producing the widest color gamut of your printer. Another issue with
printers is dot gain. Dot gain is a phenomenon whereby as ink hits the paper surface, the dot
size increases due to absorption of the ink onto the paper. Dot gain is often a necessary spec-
ification to know for those in prepress; however, when building ICC profiles, this is accounted
for when the patch targets are measured. The targets undergo dot gain and the Spectropho-
tometer and software have the necessary measurement data to account for this.
