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127
Adobe Photoshop Help
Producing Consistent Color (Photoshop)
Using Help
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Contents
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127
Use the following guidelines to determine the best method of accounting for dot gain:
•
If you are using a custom CMYK profile, use the dot gain settings in the custom CMYK
dialog box to adjust dot gain so that it matches the printed results.
•
If you are using an ICC profile and the dot gain values do not match the printed results,
try to obtain a new profile with values that do match.
•
Use transfer functions only if neither of the previous methods is an option.
To adjust transfer function values:
1
Use a transmissive densitometer to record the density values at the appropriate steps in
your image on film.
2
Choose File > Print with Preview.
3
Select Show More Options, and choose Output from the pop-up menu.
4
Click the Transfer button.
5
Calculate the required adjustment, and enter the values (as percentages) in the Transfer
Functions dialog box.
For example, if you specified a 50% dot, and your imagesetter prints it at 58%, an 8% dot
gain occurs in the midtones. To compensate for this gain, enter 42% (50% – 8%) in the 50%
text box of the Transfer Functions dialog box. The imagesetter then prints the 50% dot
you want.
When entering transfer function values, keep in mind the density range of your image-
setter. On a given imagesetter, a very small highlight dot may be too small to hold ink.
Beyond a certain density level, the shadow dots may fill as solid black, removing all detail
in shadow areas.
Note:
To preserve transfer functions in an exported EPS file, select Override Printer’s
Default Functions in the Transfer Functions dialog box and then export the file with
Include Transfer Functions selected in the EPS Format dialog box. (See
“Saving files in
Photoshop EPS format (Photoshop)” on page 448
.)
To save the current transfer function settings as the default:
Hold down Alt (Windows) or Option (Mac OS) to change the Save button to —> Defaults,
and click the button.
To load the default transfer function settings:
Hold down Alt (Windows) or Option (Mac OS) to change the Load button to <— Defaults,
and click the button.
Printing a hard proof
A hard proof can help you check the accuracy of a custom CMYK working space profile.
You can produce a hard proof by printing a CMYK image. Do not print an RGB image that
has been converted to CMYK in Photoshop. Instead use an image that has been saved in
CMYK format without an embedded ICC profile and whose CMYK values have been
assigned directly in CMYK mode.
