Graphics Programs Reference
In-Depth Information
Fig. 9-10-3
The
Curves
dialog should have the
gradient running as seen
here, where black is
indicated by the curve
point in the lower left
corner of the dialog. Here I
have also clicked on the
black curve point at the
very bottom of the dialog
and the
Input
and
Output
data entry fields are
editable.
unlock and show a value of zero in both. If not, you can enter
a value of zero in each field. Make sure you highlight the
Output
field by clicking inside it.
10.
At this point, you will move the black curve point up one
numeric value at a time. To do this, simply press the
up arrow
key on your keyboard once. The output value will change from
zero to 1. If instead the values pops up to 2, enter 1 into this
output field and all subsequent pressing on the up arrow will
ensure only one value is added. Keep pressing this up arrow
key until you can just see the separation from the rectangle
marquee. That is, you want to just barely see the rectangle. You
may need to press the up arrow key several times. Ideally, you
want to see separation between a value of 0 and 1. I can see
this on the Artisan. Most displays will have to be set for a value
higher; 4 to 6 isn't unusual. What this shows us is the accuracy
of black and the ability of the calibration and profile to
distinguish the subtle differences between zero and 1. If you
think about it, a square with 1 is lighter than a square with 0.
If you are editing very dark values in Photoshop and trying to
set them precisely, it's harder to do when you can't see them,
of course.
11.
Keep moving the up arrow slowly once you see the separation.
The next thing you want to do is examine how neutral each
step is. Not only should each step show the same density
difference from the last, but also each progressively gray step
should be neutral. It is not uncommon to see a gray square go
from neutral, to slightly green, to slightly magenta, and back
