Do not decrease brightness by more than 20 points.
Brightness and contrast calibration errors may occur if you select val-
ues that exceed the CRT's internal calibration range. This occurs
mostly when the brightness is increased (i.e., brightness values are de-
creased) by more than 20 points for any color. If the desired brightness
level is not achieved before a calibration error occurs, repeats must be
added. Refer to Chapter 7 for how to recover from a calibration error
(93).
Get the numbers as close as you can.
As you color balance your film recorder, your film may not match your
goal densities exactly. You have succeeded if your grayscale is well-bal-
anced but your curve is 10 under goal across the entire curve.
Beware of channel cross-over.
Channel cross-over occurs when a change to the brightness or contrast
in one channel causes changes to another channel. Expect cross-over
when you make large adjustments during initial trial bracketing. As
you increase your experience with the PCR II Plus, you will learn to
gauge how much cross-over to expect from your changes.
Sacrifice white/black for good-looking midtones.
You may not be able to pull out every bit of cross-over and maintain a
perfect white or dark shadow. Errors or cross-over in the curves is
most obvious in the mid-tones, although, past a certain point, white
looks white and black looks black to all but a few eyes. You may want
to sacrifice a perfect white or black for the sake of improved midtones.
Reading and Plotting Densities
Instead of taking measurements of all sixteen boxes for every test
image, you may want to measure just 5 of the boxes. Normally, boxes
2, 4, 8, 12, and 16 give you enough data to analyze and plot a curve.
Remember, Dmin—box 1—is a product of variables over which the PCR
II Plus has no control.
6-14 • PCR II Plus User Guide
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