Graphics Programs Reference
In-Depth Information
far above that of the filament. This amber light coming out of the back must be
totally absorbed by the fixture so as not to pollute the room with the wrong
color of light (about 2000K). In addition, the light coming out the front, (but at a
wide angle to the beam), which is coming directly from the filament, must also
be absorbed by the fixture because it is about 3000K. Only the model L2770
fixture achieves sufficient absorption of this unwanted light coming from the
lamp. If you want to illuminate a print as large as a full sheet from a large
format Epson printer, all you need to do is have two fixtures and adjust them
accordingly. This is a wonderful solution to an obnoxious problem, that I love
using every day.
Evaluating Your Hard Work
If you've made it this far, you've seen that building, editing, and cross-
rendering with ICC profiles provides many options. Chapter 9 has several
tutorials that can assist you in creating files that are good for evaluating
the quality of your output profiles. There are two basic techniques for
examining the quality of an output profile. One involves using statistical
methods of comparing the measured data with the expected data and
requires third-party software. The second approach is to use the two
excellent instruments on either side of your nose along with a good light
box. Output a number of tough-to-print images, such as those discussed
in Chapter 9 and simply look at the results. This is the quickest and easiest
way to find issues with output profiles.
Some areas to look for: a spectral gradient will show areas that
produce banding, which could indicate one or more patches sampled
incorrectly. This can also be an indicator if too few patches were printed
and measured for the resulting profile. Look at saturated blues in the
gradient. It's common to see a shift in these colors going either magenta
or cyan. Also, look at a black-to-white step wedge to examine good gray
balance and tonal separation. If any of these areas looks poor, the issues
could be due to an incorrect patch reading. More than a few such patch
readings will produce obvious banding or even psychedelic colors on soft
proof and output. Try to remeasure the suspect patches or simply start
from scratch. Some profile building products will report statistics after
generating the profile as seen in Fig. 6-39. This can sometimes be useful
feedback but you will still need to test the output using well-designed
test imagery. See Chapter 9, Tutorial #12: “Making a Printer Test File,”
and Tutorial #13: “Evaluating Your Output Profiles.”
