Graphics Programs Reference
In-Depth Information
the
Print with Preview
command after setting the U.S. Web Coated (SWOP)
v2 profile in the proof setup (see “Print with Preview” in Chapters 2 and
9). Another key to matching the two processes is to select the absolute
colorimetric intent due to its ability to simulate paper white on the final
print/proof.
With two output profiles, the CMS understands the CMYK press
behavior
and
the RGB Epson behavior. This ensures that the color
conversion is such that the Epson now can simulate the SWOP printing
condition. The absolute colorimetric intent ensures that the paper white
of the SWOP paper is simulated on the Epson paper. The white of the
Epson paper is different from the white of the paper that will be used on
the press. The profile contains this information. Using the absolute col-
orimetric intent causes the Epson to apply ink onto the paper white areas,
producing a match of the paper white of the SWOP coated process.
Cross-rendering allows us to make one printing condition simulate
another, which is a fantastic capability. Cross-rendering can used for RGB
device matching as well. The Fuji Pictrography can simulate a Lightjet or
Lambda print with two accurate output profiles for each device. I can
output a small 8 ¥ 10 print on my Pictrography to inspect the color before
I have a 30 ¥ 40 print made on the Lightjet from my service provider.
This is taking soft proofing one step farther. Cross-rendering forces us to
make an actual print, but often this
preproof
print is far less expensive
than the final output process. Good cross-rendering saves time and
money. Cross-rendering is also useful when you have two similar devices
and must produce similar appearing prints for a customer. Suppose you
have a small format and large format ink-jet printer and a customer needs
a print of the same file from each device. They have to match. Cross-
rendering accomplishes this task.
What are the limitations of cross rendering? The printer used as the
proofing device must have a color gamut that is as large or larger than
the printer it is trying to match. Viewing 3D gamut maps of two printers
using utilities is very useful, and is discussed in Chapter 8. In the case of
the Epson 2200 and SWOP press sheet, the Epson has a larger color
gamut so it can easily reproduce the colors from the SWOP press. The
Fuji Pictrography and Lightjet gamut are close enough whereby using
two ICC profiles produces an amazingly close match. However, an Epson
2200 would not be a very good device to cross-render a Lightjet as the
latter has a larger gamut in colors like red.
As discussed, the Epson driver requires RGB data so we produce RGB
output profiles. The conversion for this cross-rendering therefore would
be CMYK (SWOP) to RGB (Epson). Cross simulation can still work when
the two devices are of different color models. If we were using a RIP for
the Epson, the paper profile could be CMYK or RGB, depending on the
product. Many RIPs have the capability to cross-render. In Fig. 6-28,
the ImagePrint RIP has an area called
Proofer
whereby you would select
the ICC profile for the ultimate output device: U.S. Web Coated (SWOP)
