Re: UCR vs GCR...or Neither - RAW CMYK?

Dan Margulis <76270.1033@...>

Dave Badger writes,

I have been using Photoshop's Medium Generation for a long time now
GCR is supposed to give you better saturation and depth in the darker
colors. I believe this to be true and think that, for example, cyan in reds
being replaced partially by black is a good thing.>>

I would think the opposite would be true. In principle the two results
should be the same. In practice, black is much stronger than cyan is, so
any variance in inking would create a color issue, especially since the
dominant magenta and yellow in the reds will have been reduced to
accommodate the black.

Using this setting means the black is more critical on press, so I would
think using UCR or Light GCR would be better for newsprint since their
plate would be less controlled or more dot gain.>>

Certainly inking generally is less in control in newspaper printing.
However, 1) the black ink used on newsprint isn't as powerful as in
commercial printing, therefore the impact of a density change isn't as
severe; 2) in commercial printing, if the black runs too heavily one of the
principal suspects always is that the pressman was attempting to compensate
for small type or type that is difficult to print because of thinness in
part of the strokes, such as Bodoni, Baskerville, or to a lesser extent,
Times Roman. Newspapers generally aren't subject to this effect because
their text face is invariably something like Excelsior or Ionic or Times
Europa that is specifically designed for legibility at the expense of

So, while I'd agree with the general policy of using a skeleton black in
newspapers, I think there's more of a case for using a heavier black than
there is in other forms of offset.

This statement seems to indicate that people who use Photoshop's Medium
GCR setting are unsophisticated users. Yet you've said one form of UCR/GCR
is not necessarily better then another.>>

Those experienced in preparing images for CMYK, especially if the target is
a press, by and large certainly favor a lighter black than the Photoshop
default. One form of black generation isn't necessarily better, except in
an image-by-image context, and except in the context of how variable one
expectst the output device to be. A lot of the reasons for preferring a
lighter black vanish if the output is going to be inkjet rather than press.

Can you further explain why you favor a skeleton black and are there any
other downsides to GCR then those you listed above?>>

In addition to the issues mentioned earlier, the services of our friends in
the color management community become more important if you're using a
heavier black. Photoshop makes the wrong assumption that black has the same
dot gain as the other inks, whereas in real life it's usually higher. But
it's very much case by case, so a lot of users have incorrect black dot
gain values unless they've really gone to a lot of effort.

If you are using a skeleton black and your black dot gain value is too low,
this isn't great but it isn't a tragedy. If you're using a heavier black
that affects colored areas, you're really risking a muddy sep.

Dan Margulis

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