When faced with multiple
problems in the same image it pays to plan out the approach before striking out
in all directions at once. Here, how much work should be done in RGB? How much
in RGB? In CMYK?
Before seeing the image,
I would have bet that, since we have a somewhat RGB-centric group, that’s where
the fun might be taking place, whereas since I have more CMYK experience I
might be doing more work there. It didn’t turn out that way.
Five of us determined
from the get-go that we were going to make at least two versions of the image
and then combine them. In four of these cases one of the versions had been
desaturated, either slightly or completely. Unless I missed it in the notes, I
was the only one who used Hue/Saturation limited to Reds, so as not to disturb
Only three people applied RGB curves and only two of them were trying to affect overall color; notably in
#209 there was a desire for a warmer, more orange red.
Only two people tried
channel operations within RGB. Both wanted to boost contrast in the red
channel, a good idea since that’s the one most responsible for shape when the
interest object is bright red. One person accomplished this by blending the
green channel into the red; the other by multiplying the red into itself.
Neither version made it to our list of favorites.
When the image starts out
this colorful, LAB doesn’t have many attractions, so few people used it. What’s
going on? If people aren’t going to use much RGB, or much LAB, surely they
don’t just convert into CMYK and get the disaster that is the default, #200. Or
A CMYK fact of life: the
lighter the desired color, the worse the possible gamut mismatch. If we were
doing pink flowers the problem would be much more severe, and we’d see a lot
more variation in the quality of our corrections.
Why? Since we can’t lay
down solid magenta ink without creating a red rather than a pink flower, we
rely on the paper itself to create lightness. This is unfortunate, since paper
is not absolutely white; it reflects a certain amount of green and of blue
light, both of which are red-killers.
The response of the
experienced CMYK practitioner is that adding more ink allows a more colorful
result, and that it is better to have the flower too dark than too gray. But
exactly how dark to make it is a tough judgment call
When an RGB file is full
of brilliant colors that CMYK can’t hold, it’s critically important that we get
them as bright as we possibly can. Here’s my favorite trick, which I
illustrated in CC2E with a picture of brightly colored cycles.
1. Assuming approximately correct colors in RGB, make two copies and
move them into LAB.
2. Copy 1: desaturate it slightly until you are sure that nothing will
be lost by moving it into CMYK.
3. Copy 2: use Color Boost or similar action to produce colors so bright
that you absolutely will lose a lot of detail on conversion.
4. Place Copy 2 as a layer on top of Copy 1.
5. Change layer mode to Color. No apparent change from Normal mode,
since the L channels of the two layers are identical.
6. Move into CMYK without flattening. Surprise! Suddenly the detail
returns, because Color mode in CMYK tries to retain the structure of the black
channel, which is responsible for a lot of the detail.
7. Add another copy of Copy 2 to the stack and set mode to Normal,
massacring detail once again.
8. Reduce its opacity to the maximum you can stand. The higher the
opacity, the more colorful, but also the more detail is sacrificed.
So by habit, I used this
elegant procedure and produced a suboptimal image. Why? Because with a lot of
colors in play, of various darknesses, it’s really hard to know whether we’ve
gotten all the color possible. Not true in this Carnival image. Getting maximum
color is a piece of cake, pretty much everybody did it. The robe is dark enough
that if we push its maximum color to 0c100m100y0k nobody will care. It’s easy
to do with CMYK curves. No need for all these gyrations when we can just attack
the detail in the CMYK channels directly.
Three other people
followed the above procedure. Meanwhile, eight people took the more direct
approach of converting into CMYK followed by blends into at least the cyan and
often the magenta channel. Of these, one (#210) used my LAB procedure as well.
The other seven, AFAIK, just glommed the file into the terrible #200 default
and then fixed it. One of the eight blenders took his blend source from within
CMYK but the other eight used RGB channels as the source: at least the red into
the cyan, and often the green into the magenta. That is a highly sophisticated
technique that I wouldn’t have expected to be so widespread. It appeared in
many of the versions we listed as favorites, including #203, #210, #211, and
Some of these people also
applied curves to the RGB channels to add contrast before blending with them.
Particular kudos to Rick Gordon, who thought to convert the Adobe RGB file to
ProPhoto RGB before using its channels as a source. ProPhoto has a much wider
gamut and isn’t impressed by how red this image is. It therefore shows subtler
detail in its channels than Adobe RGB does.
Beyond that there was
some variation, but few surprises. Two of us experimented with different
rendering intents on conversion. One person created an entire layer of
0c100m100y0k and used it, masked, for various purposes. Six people used CMYK
curves, sometimes through a network of masks. Two used Selective Color to
enhance the shadows.
All in all, an excellent