Graphics Programs Reference
In-Depth Information
both the Forward transform (AtoB) and Inverse transform (BtoA), just the print (output) will be
affected, and the soft proof will remain unchanged.
Figure 6-29 shows the interface from Monaco's Profile Editor module where a user is asked
to specify what part of the profile they wish to edit. Notice they use the terms forward or reverse
direction. Think of the profile has having a direction moving from device to PCS to device and
this makes sense. The three options shown in this figure are explained in the lower area of the
interface. Inverse Table Editing (BtoA) is Lab (PCS) to device color. The text explains that the
colors from the output device are affected. Forward Table Editing (AtoB) is device color to LAB
(PCS). This would be the option to pick for altering the soft proof of the profile while leaving
the output portion alone. The last option is Forward and Reverse (BtoA and AtoB) tables. This
would affect both preview
and
output portions of a profile. The results are just the print portion
of the profile showing a change when the profile is used.
There are a number of profile editors available and they range a great
deal in capabilities, cost, and ease of use. These editors usually work in
a similar fashion whereby a user opens an image, usually in the output
space of the profile to be edited. Various tools are provided to alter the
color and tone of the image. The edits are not applied to the image but
rather to the ICC profile. A new, modified ICC profile is generated and
then tested. Most of the packages provide tools similar to what you would
find in Photoshop, such as levels, curves, and simple sliders to affect
brightness and contrast. Some products have very useful and sophisti-
cated selective color controls, which I find to be the most necessary tools.
This is what I would use to globally select a range of reds to remove a
yellow bias.
Like editing an image, editing a profile should be conducted in a
fashion where you correct the largest color issues first. All edits are
applied globally. That being the case, the global edits should address tone
and colorcasts first, and then smaller issues like selective color. However,
profile editing should never be used to “fix” poor quality profiles. That's
an exercise in futility! If a profile appears a tad dark or light, then a slight
tone correction is appropriate. If a profile appears to produce neutrals
with a slight cast, this can be addressed with a good editor. Anything
more invasive requires that you generate a new profile.
Some profile editors can handle only output profiles; others allow
users to edit input (scanner, digital camera, and even working space) pro-
files as well. I rarely need to edit an input profile, although the capabil-
ity is useful for tweaking a digital camera profile. I discussed how a user
can edit the target image used to build a profile for a digital camera or
scanner. The next step would be to edit the input profile itself. If you find
this necessary, be sure that your profile editor can handle input profiles.
Editing a display profile goes against everything I believe to be true about
display calibration and profiling. Some packages give you the ability to
edit a display profile but you've been warned! The real benefit of a profile
