Adobe PHOTOSHOP 5.0 User Manual page 101

If you are using ICC profiles and the on-screen
image doesn't match the printed proof closely
enough, you can do the following:
Check that the printer is not miscalibrated. It
•
may not match the dot gain specified in its ICC
profile. Adobe Systems strongly recommends that
you calibrate the imagesetter using the manufac-
turer's calibration software or a third-party image-
setter calibration device, such as Precision Color
by Kodak. If you are using a service bureau, verify
that the imagesetter is not off by more than 1
percentage point.
Get a more accurate ICC profile from the
•
printer's manufacturer.
Create an ICC printer profile using hardware
•
designed for this task. (See the documentation that
came with the ICC profile creation hardware.)
Adjust the dot gain using transfer functions. (See
•
"Compensating for dot gain in film using transfer
functions" on page 95.)
Instead of using ICC profiles, define your CMYK
•
space using the Built-in option in the CMYK Setup
dialog box. (See "Entering CMYK setup infor-
mation" on page 86.)
About dot gain
Dot gain or loss can occur when the specified
printer's halftone dots change as the ink spreads
and is absorbed by paper. Photoshop calculates
dot gain as the amount by which the expected dot
increases or decreases. For example, a 50%
halftone screen may be read with a densitometer at
an actual density on the printed page of 55%. In
this case, the dot gain would be 5%. Dot gain can
also result when a miscalibrated imagesetter is
used during the imaging process.
The dot gain estimate in the CMYK Setup dialog
box represents dot gain for a specified paper stock
for the midtones (the 50% pixels). Photoshop uses
this value to create a dot gain curve that adjusts for
dot gain throughout the image.
Note: If you will be printing separations, consult
your printer service bureau for recommended printer
dot gain settings.
The default dot gain estimate reflects the expected
dot gain between film and final output. (The dot
gain between the color proof and the final output
is typically between 2% and 5%.)
Proof (no dot gain), and printed image (with dot gain)
ADOBE PHOTOSHOP 5.0 93
User Guide